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joeb33050
01-30-2009, 08:31 AM
“The bullet must fit the throat.” We’ve heard it and read it and believed it, but after thinking about it I realized that it ain’t very helpful and I don’t know what it means and it doesn’t tell the accuracy seeker what to do.
I’m not talking here about custom molds or chamber reaming or advanced cast bullet wizardry, I’m talking about what the average cast bullet shooter like me can do to get the bullet to fit the gun and shoot accurately.
We’re told the importance of chamber casts or swaged lead forgings, of poking lead items through the bore to measure bore and groove dimensions, of bumping up bits of lead at various places in the barrel to get bore and groove dimensions at that point.
We have such words as “chamber”, “throat”, “ball seat”, “lead/e” and “free bore”, with some confusion among them.
There seem to be a wide variety of designs of rifle chambers from the end of the cartridge case to the point where the lands are at their full height and are not cut in the chambering process.
If I buy a Knurlman mountain carbine, model of 1879, and want to shoot it, I will probably end up bumping bits of lead in the chamber and bore to get some dimensions. But that’s because I don’t know much of anything about the Knurlman’s inside dimensions.
If I buy a 308 Winchester or 30/06 Springfield or a bunch of other caliber rifles, I don’t do any bumping or casting or measuring; I try some bullets and get the gun to shoot without any of this scientific business.
Rifles made in the USA for the past 50 years or so have pretty well controlled barrel and chamber dimensions, and measuring does the accuracy seeker little good.
Here’s what I think about bullet fit, and a method of understanding how to do it.
Bullet fit
The sized bullet must fit in an unsized case that has been fired in the gun. If the bullet is too big to be pushed into a fired case by hand, it is too big to be fired safely!
The cartridge should chamber with a bit of resistance.
The bullet should not stick in the chamber when the chambered cartridge is extracted. No de-bulleting!
The base of the bullet should be in the neck, not down inside the case. If just the gas check is below the neck, there’s generally no problem.
The nose of the bore-riding bullet should be engraved by each land of the rifling.
The forward-most end of the front base band should slightly mash into the origin of the rifling or the smallest diameter of a tapered free bore.
Increasing the amount of tin and/or antimony in the alloy yields slightly larger bullets.
Sizing the bullet in a lubrisizer makes the nose bump up larger.
Bigger as-cast to sized differences make the nose larger than smaller differences. Size a .314” to .308” and the nose will bump up more than when sizing from .314” to .312”.
Softer bullet noses bump up more than harder bullet noses.
Bullets with base bands sized to different dimensions may/will produce different maximum overall cartridge lengths.
Rifle barrel lands at the chamber end wear or erode, so that cartridge overall length increases slightly and slowly as the rifle is shot.
If the cartridge that goes in the gun has a lot of base band below the neck, change something.
If the cartridge goes in the gun, has just the gas check in the case mouth and doesn’t engrave the bullet nose, change something.

If the accuracy seeker understands this, and fiddles with some of the commonly available bullets/molds, he will be well on the road to success without casting or measuring anything on the gun.
Can this be true?

BPCR Bill
01-30-2009, 09:03 AM
I assume you are refering to casting and loading bullets for smokeless ammunition and modern firearms. I have done this minmally for a 30-40 Krag, but my main experiences over the last 20 or so years has been with Black Powder Cartridge. Maybe a couple points I can put out here to get the discussion rolling. You refer to a Bore Riding nose engaging the rifling. Nope, at least not in my experience. The bore rider nose does just that, it is at bore diameter, and it's purpose is to help align the projectile in the bore, center to bore axis. It does not engage the rifling. The front band on the cast lead boolit is called the driving band, and it can be safely engaged in the rifling. The driving band and all others should be cast to groove diameteror maybe+.001". In BPCR there are match reamers that are ground to provide a "Lead Angle" on the rifling that is a bit less steep than the standard chamber would, providing a less abrupt transition into the barrel. Lead will "Bump Up" to some degree on firing anyway. There are those that argue for the match chamber and those that discount it. And you are correct, hardening a boolit with tin or antimony will increase the diameter of said boolit. Lets see what others chime in with.

Regards,
Bill

runfiverun
01-30-2009, 09:26 AM
joe:
you are referring to boolits such as the rcbs silhouette style.
which are of course bore riders they are pretty critical in this area a bit of engraving is helpful.
how much is a product of your alloy, as like you said they must de-chamber [for safety].
but with other designs,the nose shape is where your fit comes in.
imagine this,.......<< put together as close as possible.
now back to the bore riders.
if your nose is too small it can and will enter the bbl on an angle or skid on it's nose or bend in the bbl or set back some at an angle during it's trip down the bbl.
this is where the tale of using lino-type in rifles originated.
as far as bumping them up in the sizer,can't help you there as i use star sizers and have to make boolits that fit my purposes through other means[alloy changes,beagling].

44man
01-30-2009, 10:05 AM
Well, maybe if you are shooting BR for a one hole group. Most of us don't notice all that junk. In 55 years of loading, I have done all of it but now I mostly ignore most.
The only thing I have learned about my revolvers is that the throat must be a little larger then the bore, just common sense. That is a mechanical problem just like bad bedding in a rifle or a rusted bore. Take my .44! The throats are .4324 but it gobbles up any good boolit from .430 to .432 just the same. I recently shot a 1-5/16" group at 200 yd's with a .431 boolit. I ate IHMSA guys for lunch with .430 bullets.
How about boolit jump to the rifling? A lot of revolver makers make real short cylinders so the boolit is real close to the forcing cone! :confused: Then I bought the BFR 45-70. The nose of the boolit is 9/16" from the end of the cylinder. It has shot 7/16" at 50, more groups under 1" at 100 then I can count and outshoots my rifle at 500 meters.
What it all comes down to is boolit design, it's match to the twist at the velocity you shoot it and if it fits the rifling tight. I can't tell a difference if a boolit is .001, .002 or .003" over bore size.
Some say shoot an undersize boolit soft so it expands, I don't believe in it, never did and never will. I shoot fairly hard boolits, up to 22 BHN. The faster the powder, the harder I want them. The only soft boolits I shoot are with BP.
I have read a million solutions to poor accuracy and barrel leading, tried and rejected 99% of it as not being worth the trouble.
If your barrel is not accurate, nothing you can do. If a boolit or bullet doesn't shoot after a thousand loads, get a different one.
After all of these years the K.I.S.S principal is still the winner.
How you assemble loads is probably more important once you have a boolit and load the gun likes. I let the gun tell me first.
If you cast 100,000 scrub boolits in a few hours and bang loads out on a Dillon so fast rounds are flying all over, don't expect a whole lot more then noise. Same if you just go to all the books looking for one that has a hotter, faster load and just shoot that one. Anyone that brags about velocity and muzzle energy never hits anything or kills an animal with every shot.
I never did all the crazy stuff with rifles and jacketed bullets either and managed to get most to shoot fantastic groups as good as or better then some BR rifles. I just learned how to load first. I don't care if it takes me 10 minutes to load one shot. I know how to pick dies and change them if needed to make straight loads.
So, JoeB, we seem to be on the same page. Yeah, I have all the special tools to do anything, but they seem to sit in the drawer an awful lot.
The thing that bugs me most are guns with the wrong twist. :Fire:
The thing I would love to play with is a .44 mag revolver with a 1 in 18" twist! :mrgreen:

Maven
01-30-2009, 01:02 PM
Bullet fit:
1) The sized bullet must fit in an unsized case that has been fired in the gun. If the bullet is too big to be pushed into a fired case by hand, it is too big to be fired safely!

Joe, this is so except when the case necks have thickened and need to be inside neck-reamed. My Ruger #1 .243Win. is guilty of this primarily with CB loads. High pressure jacketed bullet loads don't thicken the necks nearly as often. Reformed brass may -> thick necks so one must be careful about the CB-in-the case-test under these conditions.

2) The base of the bullet should be in the neck, not down inside the case. If just the gas check is below the neck, there’s generally no problem.

As I wrote to you once before, Jim Carmichael tested this with a .243Win. and CB's (Ly. Loverin #245496) seated so that it would engage the rifling normally v. seated with all the lube grooves in the case (OAL was ~2.29") and found no difference in accuracy, but a ~100 fps increase in velocity. (The article was in "Handloader" some years ago.) Moreover, the short neck and even shorter throat of the Swiss K-31 (7.5 x 55mm; at first glance looks like a .308Win. case) pretty much means you'll be seating 175gr. or heavier CB's with the gas checks below the neck-shoulder junction, yet accuracy is unaffected. Lastly, I have a .45-70 Marlin #336 (Microgroove rifling), in which I seated the CB's long enough to be engraved by the rifling exactly as you've described. Accuracy was excellent, but seating in that manner meant the OAL of the [loaded] rounds was excessive (2.66" - 2.67") and couldn't be fed via the loading gate. I.e., they had to be loaded individually. As you can imagine, one tires of that quickly and thus decided to load "normally," i.e., to 2.55" OAL. Accuracy was unchanged. In short, I follow your advice >90% of the time, but in some rifles, it may not have the effect we expect, but I'm not sure why.

3) The nose of the bore-riding bullet should be engraved by each land of the rifling.
This is almost axiomatic, but there are exceptions that I can't explain. For example, I use #314299 sized to either .313" or .314" in my Argentine Mauser (Mod. 1909) with impressive 100yd. accuracy given its miserable sights and well-worn bbl. However, no matter what I did, it would generally throw one shot out of group. Since I was baffled by this, I pushed a few slugs through the bbl. (breech -> muzzle) and noticed the nose wasn't marked at all by the rifling. 30 mins. ago, I retested this by placing a #314299 directly into the muzzle: The nose was unmarked until ~1/16" ahead of the driving bands. Although #314299 doesn't ride the bore of that rifle well, its performance is predictable and very good. However, the CBE fat Loverin I now use has eliminated all flyers. Thus, a less than perfectly fitting bore-rider may produce very good results if everything else is done correctly.

Larry Gibson
01-30-2009, 03:10 PM
Joe

For a good "fit" the average reloder should look for two things; first, the nose of a bore rider should be slightly engraved by the rifling begining at the ogive back to where the rifling begins. This engraving of the bullet nose should be equal with all of the lands around the bullet nose. If it is not equal then the ammo has concentricity problems that need solved elsewhere. However, if the average shooter with his average bolt action rifle has a bullet nose of .001-.002" less than land diameter and does not engrave good accuracy can still be had if the bullet is cast of an alloy of 18+ BHN. This is becase if the second item is correct the bullet nose will stay concentric until the pressure/accelleration rate becomes too much for the alloy stregth and the bullet nose bends to the side as the lube groooves collapse unevenly.

Second, the dirving bands that enter the leade on chambering the cartridge should equal to or .0005" less than the leade diameter. The leade is defined in "Firearms Encyclopedia" as; "the origin of the rifling in a rifled barrel. It is that portion of the bore immediately ahead of the chamber mouth in which the rifling lands have been cut away to allow entry of the bullet." The driving bands that do not enter the leade on chambering can be of .001-.002" larger diameter and are swaged down by the leade ensuring a positive gas seal and alignment.

Your methods of obtaining/measuring that "fit" are sound and should be easy enough for the reloader/cast bullet shooter to follow. They work for me.

Larry Gibson

Bret4207
01-30-2009, 03:56 PM
“The bullet must fit the throat.” We’ve heard it and read it and believed it, but after thinking about it I realized that it ain’t very helpful and I don’t know what it means and it doesn’t tell the accuracy seeker what to do.
I’m not talking here about custom molds or chamber reaming or advanced cast bullet wizardry, I’m talking about what the average cast bullet shooter like me can do to get the bullet to fit the gun and shoot accurately.
We’re told the importance of chamber casts or swaged lead forgings, of poking lead items through the bore to measure bore and groove dimensions, of bumping up bits of lead at various places in the barrel to get bore and groove dimensions at that point.
We have such words as “chamber”, “throat”, “ball seat”, “lead/e” and “free bore”, with some confusion among them.This was discussed at length some time ago and nearly resulted in a small war. Your best bet is to refer to the SAAMI definitions and don't get Mike going about it
There seem to be a wide variety of designs of rifle chambers from the end of the cartridge case to the point where the lands are at their full height and are not cut in the chambering process.Again, SAAMI has drawings of standard seats
If I buy a Knurlman mountain carbine, model of 1879, and want to shoot it, I will probably end up bumping bits of lead in the chamber and bore to get some dimensions. But that’s because I don’t know much of anything about the Knurlman’s inside dimensions.
If I buy a 308 Winchester or 30/06 Springfield or a bunch of other caliber rifles, I don’t do any bumping or casting or measuring; I try some bullets and get the gun to shoot without any of this scientific business.
Rifles made in the USA for the past 50 years or so have pretty well controlled barrel and chamber dimensions, and measuring does the accuracy seeker little good.
Here’s what I think about bullet fit, and a method of understanding how to do it.
Bullet fit
The sized bullet must fit in an unsized case that has been fired in the gun.Fired with a full power load, not a mild load. If the bullet is too big to be pushed into a fired case by hand, it is too big to be fired safely!Usually, there are rare exceptions
The cartridge should chamber with a bit of resistance.Not necessarily, the boolit can enter the throat/seat without interference and chamber smoothly
The bullet should not stick in the chamber when the chambered cartridge is extracted. No de-bulleting! Not for a hunting load anyway.
The base of the bullet should be in the neck, not down inside the case. If just the gas check is below the neck, there’s generally no problem.Not an issue at all unless you're working max loads and lose powder space or have a lube that will migrate to the powder
The nose of the bore-riding bullet should be engraved by each land of the rifling.Define "engrave", and good luck doing it without pics
The forward-most end of the front base band should slightly mash into the origin of the rifling or the smallest diameter of a tapered free bore.Depends on the design, some bore riders won't allow that, and some other designs won't either. This is where those pesky "sometimes", "occaisionally", "may", "may not" words creep up Joe. I know you hate that.
Increasing the amount of tin and/or antimony in the alloy yields slightly larger bullets.Better get a better description of how and why
Sizing the bullet in a lubrisizer makes the nose bump up larger.Not unless you "bump" it accidentally or on purpose. Some dies just act as lubers, have to use a fuller description, "...be aware if you're reducing the as cast diameter at all the 'sizer can bump the nose larger..."
Bigger as-cast to sized differences make the nose larger than smaller differences. Size a .314” to .308” and the nose will bump up more than when sizing from .314” to .312”.Good example, the boolit will also usually enlongate
Softer bullet noses bump up more than harder bullet noses.In general, can be controlled
Bullets with base bands sized to different dimensions may/will produce different maximum overall cartridge lengths.
Rifle barrel lands at the chamber end wear or erode, so that cartridge overall length increases slightly and slowly as the rifle is shot. BA is the guy to describe that
If the cartridge that goes in the gun has a lot of base band below the neck, change something.Why? It's meaningless except ing the cases I described earlier
If the cartridge goes in the gun, has just the gas check in the case mouth and doesn’t engrave the bullet nose, change something.Again, why? You need a fuller description, "...in many cases a boolit whose nose is not engraved or supported at the throat will benefit from ruthless runout checks. Minimum runout and a fireformed case will help make up for lack of nose support or an undersize nose, but won't fix it all..."

If the accuracy seeker understands this, and fiddles with some of the commonly available bullets/molds, he will be well on the road to success without casting or measuring anything on the gun.
Can this be true?

Yes, it can be true but a great deal rides on the shooter understanding the basics of building an accurate load and of fitting the boolit to that gun. IMO fit is King with cast. Anything you do to improve fit will benefit you, anything you do to make the fit worse will hurt you.

I wish you luck Joe, you've taken on a tough quest. Putting this into words with pictures to aide you will be tough.

joeb33050
01-31-2009, 07:57 AM
Bret;
How do you reply in BOLD in the middle of the post? Can't figure it out.
Thanks;
joe b.



Yes, it can be true but a great deal rides on the shooter understanding the basics of building an accurate load and of fitting the boolit to that gun. IMO fit is King with cast. Anything you do to improve fit will benefit you, anything you do to make the fit worse will hurt you.

I wish you luck Joe, you've taken on a tough quest. Putting this into words with pictures to aide you will be tough.

joeb33050
01-31-2009, 08:01 AM
ABOUT CHAMBERS AND THROATS

In a rifle, there is a shape cut out of the rear of the barrel to fit the cartridge.
From the end of that space forward there are any number shapes that can be cut-from the cartridge case mouth to the point where the lands and grooves of the barrel are untouched.
Parts of these shapes have names, and these names are not agreed upon.
The purpose of this paper is to show typical barrel breeh end cut shapes and the names for these shapes and their parts.

First we have a 30-30 chamber, with little in the way of a transition:




Then the 30/06


(Thanks to Pat Iffland for these drawings.)



Then a "custom" transition:



(Thanks to Dan Willems for the drawing.)
Definitions vary, here are some:

BALL SEAT
The cylindrical section of the barrel cut just in front of the cartridge case
Ball Seat is sometimes called the FREE BORE or LEAD.

CHAMBER
The CHAMBER is the part of the barrel cut to fit the cartridge case.
The CHAMBER is all of the cut part of the barrel between the cartridge case head and the point where the lands are uncut.

FREE BORE
In a rifle chamber THROAT is also known as FREE BORE and is supposed to be groove diameter with the rifling cut out.
FREE BORE - the portion of the barrel from the end of the chamber to the beginning of the THROAT that is free from any rifling.
(Note: The term "free bore" or "freebore" is associated, by some people, with Weatherby rifles, where a longer unrifled area ahead of the case mouth was said to allow increased velocity with acceptable pressures.)

LEADE (LEAD)
The LEADE is the section of the bore of a rifled gun barrel located immediately ahead of the chamber in which the rifling is conically removed to provide clearance for the seated bullet. Also called THROAT or BALL SEAT.
The LEADE is is the area of rifling (lands) that begins at the end of the THROAT, and extends to the point where the lands attain their full height.
The LEADE is the area of the barrel from where the angle of the THROAT begins to where it reaches bore diameter.

THROAT
THROAT is the angled portion of the transition.
THROAT is the area from the chamber mouth to the rifled bore.
In a rifle, the THROAT is the unrifled portion of the barrel between the chamber mouth and where the lands begin.
On a revolver, THROAT is the part of the chambers at the front of the cylinder where the bullet rests (or should), )
In a rifle chamber THROAT is also known as FREE BORE and is supposed to be groove diameter with the rifling cut out.

Pat I.
01-31-2009, 09:11 AM
Joe a couple of problems with your "custom" throat drawing. First it's not custom it's a ball seat throat used in a lot of applications, the .308 Win. being one example. The only difference between this and a custom throat is diameter, length of the ball seat, and the taper of the throat. Second the transition from the chamber to the ball seat area isn't square like in the picture but tapered.

The terms ball seat, lead, and free bore are all interchangable with Weatherby using free bore because on their rifles it's cut longer to allow higher velocities without going over the top with pressure. Personally I wish they would have just picked one term like in my chamber print book, lead for the straight section and throat for the tapered. Solve a lot of confusion that way and we could stick with the term throat to describe it all.

44man
01-31-2009, 09:31 AM
Fellas, you all know that the important stuff can be counted on the fingers of one hand, stuff we should all know before even starting to load. No need getting into detail on it over and over.
Now in the first post, much other tweaking is mentioned and that is for play time after we find a decent boolit and load.
My answer was to show the actual first stage is pretty easy and is where the wrong boolit or twist or gun itself is suspect for poor or good accuracy.
The worst thing to do is to get involved in all of the tweaking all at once hoping to turn a pig's ear into a silk purse! [smilie=1:
Follow the basics first and if it doesn't pan out, change the boolit. Changing seating depth a few thou, etc, will not help if the basics prove something drastic is wrong.
There is much truth in the first post but do the simple first, following what we know should work.
There must be 10,000 posts asking how to get a certain boolit to shoot from such and such gun, 30,000 answers, well, if the initial work was done and didn't pan out, dump the boolit!
The next 10,000 posts will ask "How fast can I shoot a cast boolit." My answer is shoot it at the velocity it is accurate at, no more or less. "But I want to see if I can get 3600 fps." Again---WHY?
The one that gripes me the most is when someone wants to shoot a 320 .44 boolit (And all the other big bores.) at 700 fps accuratly because it kicks too much, that one really makes me laugh! :mrgreen: Might be time for a .22. :drinks:
30,000 answers to a mismatch is a waste of time, money, components and causes hair loss. Makes a lot of money for whiskey makers too! :Fire:
K.I.S.S first.
I can reject a boolit in about 20 shots but I see this post will go on for the next year.

felix
01-31-2009, 10:38 AM
Agree, 44man. If not the bullet, then it is the barrel (revolter barrel = cylinder + barrel). A lot of times the gun will adjust itself over time when shooting projectiles to wear in the barrel. 99 percent of the guns out there are not concentric from start to finish. Your BFR is an exception, much like the custom BR guns, and therefore does not qualify as material for Joe's discussion(s). Why 20 shots? Normally, it would take three 3-shot groups to decipher that something is wrong with either boolit or gun. But then, the accuracy requirement might not be so critical either. ... felix

montana_charlie
01-31-2009, 12:27 PM
Your BFR is an exception, much like the custom BR guns, and therefore does not qualify as material for Joe's discussion(s).
Agreed...but not because of the custom nature of the firearm. The comments are not material because Joe is talking about bullet fit in rifles...not revolvers.

In revolver-speak, terms like 'bore rider', and 'seat to engage the rifling' have no meaning. The only 'bullet fit' requirement is that the bullet be small enough to escape the cylinder without severe damage.
A revolver's 'throat' is merely that part of the cylinder which is not part of the chamber cut. And, a forcing cone takes the place of a rifle's leade...being a simple funnel that directs the bullet into the barrel.
Leading in the forcing cone is common...almost expected.
Leading in the leade of a rifle is a sign that something is seriously wrong.

Very little that can be said about revolvers has any application at all when speaking about rifles.

When it IS understood that the discussion centers on rifles, 'bullet fit' has two elements.

- There is the basic requirement that the bullet fill the empty space within the chamber/freebore/leade area sufficiently that bump-up (a modification of the original bullet) is kept to a minimum.

- And, there is the advantage to be gained if the 'fit' of the bullet to the topography of the 'throat' (an all-inclusive term which I use to cover the freebore - if one exists - and the leade) is such that two points on the bullet are firmly supported by barrel steel when the loaded round is chambered.

In some rifle designs, this two-point contact may not be possible because COAL must be kept short enough to cycle through the action.

CM

http://castboolits.gunloads.com/picture.php?albumid=88&pictureid=475

44man
01-31-2009, 12:33 PM
Agree, 44man. If not the bullet, then it is the barrel (revolter barrel = cylinder + barrel). A lot of times the gun will adjust itself over time when shooting projectiles to wear in the barrel. 99 percent of the guns out there are not concentric from start to finish. Your BFR is an exception, much like the custom BR guns, and therefore does not qualify as material for Joe's discussion(s). Why 20 shots? Normally, it would take three 3-shot groups to decipher that something is wrong with either boolit or gun. But then, the accuracy requirement might not be so critical either. ... felix
Need to try a few loads, sometimes it takes me 25 to cover the velocities. I always shoot 5 shot groups with any gun. Once it shoots good, I switch to 3 shots for sighting. Some guns are so good, I can sight with one shot between sight changes.
Yes, every BFR I have and that my friends have brought over all have perfect bores and throats but we have had great luck with new Ruger's that never see a J bullet.
But breaking in a new rifle barrel is one of the basics and that should have been done properly before cast is sent down them. Then again, most rifle shooters that switch to cast have had their rifles for a long time and they should be smooth. All of us here know that, unlike the hunters that brought me rifles that quit hitting deer. Takes me a week with Sweets to get out the copper! [smilie=1:I should sell the patches for scrap! :mrgreen: Others have stock and scope screws loose, others have stock screws so tight they bend actions but again those are all basics
I know we have a lot of beginners come here and some of the detail confuses them to no end. Sometimes, plain, simple answers will get them started.
The reason I know this is I get a lot of E mails asking things. It takes a long time to help. They read a lot here and other sites and keep coming up with stuff they don't need or it is too early to play with. It takes a lot of convincing to get them to relax.
So although none of you are wrong in any way, sometimes it is better to back up a little. Me, you and everyone else here with years of experience are guilty of jumping into a new project with both feet, overlooking the starting point because something worked in another gun or with another boolit.
Yeah, me too, trying everything all at once! :Fire:

Bret4207
01-31-2009, 07:04 PM
Bret;
How do you reply in BOLD in the middle of the post? Can't figure it out.
Thanks;
joe b.

Use the "Quote" reply function, then just add your comment within the "quote" area. The "bold" option is that heavy, dark "B" to the lower left of your fonts choice area above the script box. You have to add at least a few words in outside the quote to get it to go. Very handy!:drinks:

joeb33050
02-01-2009, 07:26 AM
Use the "Quote" reply function, then just add your comment within the "quote" area. The "bold" option is that heavy, dark "B" to the lower left of your fonts choice area above the script box. You have to add at least a few words in outside the quote to get it to go. Very handy!:drinks:

For some reason there is no fonts choice area above the script box. None. Either I have something turned off, or you guys are kidding me.
joe b.

joeb33050
02-01-2009, 07:52 AM
Well, maybe if you are shooting BR for a one hole group. Most of us don't notice all that junk. In 55 years of loading, I have done all of it but now I mostly ignore most.
The only thing I have learned about my revolvers is that the throat must be a little larger then the bore, just common sense. That is a mechanical problem just like bad bedding in a rifle or a rusted bore. Take my .44! The throats are .4324 but it gobbles up any good boolit from .430 to .432 just the same. I recently shot a 1-5/16" group at 200 yd's with a .431 boolit. I ate IHMSA guys for lunch with .430 bullets.
I suggest that you shoot five five-shot groups at 100 yards, on one sheet of paper, photograph that target with the group sizes clearly noted, and once and for all quiet those who suggest that your groups may be imaginary.


How about boolit jump to the rifling? A lot of revolver makers make real short cylinders so the boolit is real close to the forcing cone! :confused: Then I bought the BFR 45-70. The nose of the boolit is 9/16" from the end of the cylinder. It has shot 7/16" at 50, more groups under 1" at 100 then I can count and outshoots my rifle at 500 meters.
What it all comes down to is boolit design, it's match to the twist at the velocity you shoot it and if it fits the rifling tight. I can't tell a difference if a boolit is .001, .002 or .003" over bore size.
Some say shoot an undersize boolit soft so it expands, I don't believe in it, never did and never will. I shoot fairly hard boolits, up to 22 BHN. The faster the powder, the harder I want them. The only soft boolits I shoot are with BP.
I have read a million solutions to poor accuracy and barrel leading, tried and rejected 99% of it as not being worth the trouble.
If your barrel is not accurate, nothing you can do. If a boolit or bullet doesn't shoot after a thousand loads, get a different one.
After all of these years the K.I.S.S principal is still the winner.
How you assemble loads is probably more important once you have a boolit and load the gun likes. I let the gun tell me first.
If you cast 100,000 scrub boolits in a few hours and bang loads out on a Dillon so fast rounds are flying all over, don't expect a whole lot more then noise. Same if you just go to all the books looking for one that has a hotter, faster load and just shoot that one. Anyone that brags about velocity and muzzle energy never hits anything or kills an animal with every shot.
I never did all the crazy stuff with rifles and jacketed bullets either and managed to get most to shoot fantastic groups as good as or better then some BR rifles. I just learned how to load first. I don't care if it takes me 10 minutes to load one shot. I know how to pick dies and change them if needed to make straight loads.
So, JoeB, we seem to be on the same page. Yeah, I have all the special tools to do anything, but they seem to sit in the drawer an awful lot.
The thing that bugs me most are guns with the wrong twist. :Fire:
The thing I would love to play with is a .44 mag revolver with a 1 in 18" twist! :mrgreen:
Just an idea!
joe b.

joeb33050
02-01-2009, 08:12 AM
Bullet fit:
1) The sized bullet must fit in an unsized case that has been fired in the gun. If the bullet is too big to be pushed into a fired case by hand, it is too big to be fired safely!

Joe, this is so except when the case necks have thickened and need to be inside neck-reamed. My Ruger #1 .243Win. is guilty of this primarily with CB loads. High pressure jacketed bullet loads don't thicken the necks nearly as often. Reformed brass may -> thick necks so one must be careful about the CB-in-the case-test under these conditions.
First, I'm told that outside turning is preferred to reaming. ???Second, if the bullet don't go in a fired case, it's too big. Or the case neck is too thick. Don't load and shoot it.
Third, I've never had CB necks thicken, and I've got cases that have been fired hundreds of times. Also never had a case head separation. Don't know why, maybe because I shoot slow.
2) The base of the bullet should be in the neck, not down inside the case. If just the gas check is below the neck, there’s generally no problem.

As I wrote to you once before, Jim Carmichael tested this with a .243Win. and CB's (Ly. Loverin #245496) seated so that it would engage the rifling normally v. seated with all the lube grooves in the case (OAL was ~2.29") and found no difference in accuracy, but a ~100 fps increase in velocity. (The article was in "Handloader" some years ago.) Moreover, the short neck and even shorter throat of the Swiss K-31 (7.5 x 55mm; at first glance looks like a .308Win. case) pretty much means you'll be seating 175gr. or heavier CB's with the gas checks below the neck-shoulder junction, yet accuracy is unaffected. Lastly, I have a .45-70 Marlin #336 (Microgroove rifling), in which I seated the CB's long enough to be engraved by the rifling exactly as you've described. Accuracy was excellent, but seating in that manner meant the OAL of the [loaded] rounds was excessive (2.66" - 2.67") and couldn't be fed via the loading gate. I.e., they had to be loaded individually. As you can imagine, one tires of that quickly and thus decided to load "normally," i.e., to 2.55" OAL. Accuracy was unchanged.
"Does accuracy decrease if the bullet base is below the case neck?" I don't know, and have tried, unsuccessfully, to devise a test. I'd like to read the article. I include that notion because there seems to be general agreement tha accuracy does degrade when the bullet is down in the powder space. I can't prove it, I understand what you wrote and your experience, yet there seem to be many who have contrary experience. I have NO experience, never had the problem. The Striker must have the 314299 seated such that only the gas check is below the neck. So I don't know, and err on the side of caution.



In short, I follow your advice >90% of the time, but in some rifles, it may not have the effect we expect, but I'm not sure why.

3) The nose of the bore-riding bullet should be engraved by each land of the rifling.
This is almost axiomatic, but there are exceptions that I can't explain. For example, I use #314299 sized to either .313" or .314" in my Argentine Mauser (Mod. 1909) with impressive 100yd. accuracy given its miserable sights and well-worn bbl. However, no matter what I did, it would generally throw one shot out of group. Since I was baffled by this, I pushed a few slugs through the bbl. (breech -> muzzle) and noticed the nose wasn't marked at all by the rifling. 30 mins. ago, I retested this by placing a #314299 directly into the muzzle: The nose was unmarked until ~1/16" ahead of the driving bands. Although #314299 doesn't ride the bore of that rifle well, its performance is predictable and very good. However, the CBE fat Loverin I now use has eliminated all flyers. Thus, a less than perfectly fitting bore-rider may produce very good results if everything else is done correctly.
My experience is that in general, on average, most of the time, when enough groups are fired to reveal the truth, that bore riders engraved by the rifling shoot better than bore riders not engraved by the rifling. Forgetting the 314299 for a bit, the 311291 is loved by all but me, because the damn molds almost never produce bullets with noses big enough to engrave. When you get a big-nose mold, the 311291 is a V.G. bullet, but not as good as the 311/314299.

I got this thing working, and I'm loving it!!!

joeb33050
02-01-2009, 08:18 AM
Joe a couple of problems with your "custom" throat drawing. First it's not custom it's a ball seat throat used in a lot of applications, the .308 Win. being one example. The only difference between this and a custom throat is diameter, length of the ball seat, and the taper of the throat. Second the transition from the chamber to the ball seat area isn't square like in the picture but tapered.

The terms ball seat, lead, and free bore are all interchangable with Weatherby using free bore because on their rifles it's cut longer to allow higher velocities without going over the top with pressure. Personally I wish they would have just picked one term like in my chamber print book, lead for the straight section and throat for the tapered. Solve a lot of confusion that way and we could stick with the term throat to describe it all.
Ken Meyer put up drawings of 30-30, 30-06 and 308 Win chambers, however the print gets too small if the dwgs fit on a page portrait style. We need some dwgs of chambers, and I can't draw. Your 30-30 and 30-06 dwgs are in the article above. Want to make some more?
Thanks;
joe b.

felix
02-01-2009, 10:10 AM
TOM MYERS, Joe! ... felix

44man
02-01-2009, 10:13 AM
As an aside, one of the fine fellas here designed a boolit for my 45-70 Browning BPCR that so far is shooting good. I have not made a shoot in two years but hope to test it more this year.
Anyway, the boolit will not go in a fired case, I have to expand it first. It is designed to fit the chamber when loaded and measures .464" with a .451" bore ride. If I remember, my bore is .4594 X .450, can't find my exact figures.
I see no harm in larger cast jammed into the chamber without the traditional .002" clearance. Might need it with high pressure jacketed loads but cast is soft and would most likely expand the boolit and brass together when touched off anyway.

One thing always unclear to me is the theory of what happens to the neck? Let's take a rifle cartridge with a long neck, hot jacketed load.
Some say you need .002" and that the neck jumps open all at once, releasing the entire bullet before it leaves the neck!
Seems to me brass is soft and ductile and expands the case starting at the rear, rolling it forward until the bullet base is reached, then can only expand the neck as the bullet moves out of the way.
If the neck jumps open all at once, doesn't a lot of gas blow past the bullet? Will it not also blow all the lube out of a cast boolit before the boolit moves? Why do we use neck tension? Why does a light load leave lube and powder outside the brass and some crimp is even left behind?
How does a revolver even work if the case springs open all at once?
Now I understand if the neck is too thick and a chambered round is so tight that the neck is forced into the bullet making it hard to move, that pressure can go through the roof. But is not .0005" enough to prevent that? Why is .002" supposed to be needed?
I will keep believing the neck can not expand until the bullet moves out of the way! This will start a storm of replys but I don't think anyone can offer real proof that the whole case springs open before the bullet can move. :kidding:I believe the .002" is nothing but a safety factor with jacketed to insure all are the same and a thick neck can't sneak in. Too hard to work with .0005".
I don't believe a whole lot of this applies to cast because if jammed into the chamber, the boolit just gets sized anyway and it is easier to move when fired. A lot of you use grossly oversize cast without a problem.
The same occurs with a jacketed bullet into the rifling, loads must be worked for it. We cast shooters can jamb a bore ride into the lands and jam the drive band into the rifling without enough change to worry about.
Now what have I started!!!!:hijack:

felix
02-01-2009, 10:33 AM
You are correct on all accounts, 44man. Ideally, you want the boolit to obturate to make zero clearance, and not a fraction of an inch more! Now, you know that depends on the factors you already know. It just so happens that I used various diameters of case necks and boolits, and found that with the majority of lots of both, my BR gun likes an 0.0008 total clearance using my fixed-standard powder and primer. How do I know? The repeatability in various ambients over the last 10 years. ... felix

Pat I.
02-01-2009, 10:34 AM
Ken Meyer put up drawings of 30-30, 30-06 and 308 Win chambers, however the print gets too small if the dwgs fit on a page portrait style. We need some dwgs of chambers, and I can't draw. Your 30-30 and 30-06 dwgs are in the article above. Want to make some more?
Thanks;
joe b.

Joe,

Since Tom's prints make my hand drawings look a little shabby with his permission I could just edit his to remove everything but the throat and neck area.

sundog
02-01-2009, 11:46 AM
Maven got it - boolit diameter should be a fit for a fire formed neck.

For a particularly good shooting rifle, neck turning is a must. There after the correct boolit diameter can be determined but only after it has been fire formed after neck turned. This means that a case needs to fired at least twice in the process. Once to initially fire form, then neck size, trim and turn, then refire, then determine the boolit diameter.

Maven's observation about seating depth is also noteworthy. Boolit base should be at the base of the neck. Then boolit length is determined to nose engraving or touching the lands. The rifle will tell you what boolits it likes as far as fit. Problem then is whether the twist and other conditions will support accuracy with a particular boolit.

44Man is right, too. Shoot it at the speed it is most accurate. The group of conditions that exist will determine the optimal velocity. Change any of the variables, and you start over.

Tom Myers
02-01-2009, 12:06 PM
Joe,

Since Tom's prints make my hand drawings look a little shabby with his permission I could just edit his to remove everything but the throat and neck area.

Pat,
As long as the integrity of the scale and values are not compromised I have no problem with cropping and moving the labels to where they are visible

As a matter of fact I am in the process of changing my chamber and composit drawing software so that, on command, only the neck, throat, bullet area at a full scale of 1 pixel to 1/1000 inch may be displayed on the computer screen without having to use scroll bars to view the entire drawing. As soon as the software changes are finished, I can post drawings that show the various relationships between cartridge, chamber, throat area and bullet.

Tom Myers
Precision Ballistics and Records (http://www.tmtpages.com)

Pat I.
02-01-2009, 12:17 PM
Tom, Thanks for replying and since you're already in the process of accomplishing the same thing I offered I'll bow out.

montana_charlie
02-01-2009, 01:09 PM
Here's a chamber drawing, copied as-drawn from the internet. It is not a bottlenecked design, but the reamer is shaped to establish a cylindrical neck area to hold the bullet.

The 'labels' agree with my understanding of how best to use the various terms. Everything to the right of the chamber step would be called 'the throat'...
CM

http://castboolits.gunloads.com/picture.php?albumid=88&pictureid=477

Pat I.
02-01-2009, 01:42 PM
Charlie, That's why this stuff just adds to the confusion. Here's a scan of the neck and throat area of a .308 from Dave Kiff's book of chamber prints. He uses Lead and Throat to differentiate between the cylindrical and tapered portions. Doesn't amount to a hill of beans either way but why in the heck didn't someone just pick one word to describe the areas being talked about and call the whole thing the "Start"?

montana_charlie
02-01-2009, 03:19 PM
Charlie, That's why this stuff just adds to the confusion.
You are right, Pat. Different people use the terms (usually the same terms) in different ways. Clymer (the reamer maker) calls the freebore a 'freebore', but uses 'throat' to label the ramped start of the rifling.
Others (Dick Trenk of Pedersoli, for one) calls the leade a 'leade', but uses "Throat (freebore)" (written that way) for the cylindrical space just in front of the chamber step.

If you look up the definition for leade (assuming you can actually find one) it is actually a part of the rifling...as in "the leade of the rifling". That refers to the angled ramp which culminates in the full depth of the rifling cut.
So, if 'leade' can be clearly identified, it's obviously not 'the throat'...as Clymer would have us believe.

If 'freebore' is defined as "The distance, if any, which a bullet travels upon firing before it contacts the origin of the rifling." then it would only be confusing to call that area 'the throat'...which many do.

If you buy a 'throating reamer', it will (depending on how it's shaped) modify, or create, both the freebore and the leade angle. In other words, it 'cuts the throat' into the desired topography. Therefore, it's very hard to get confused if everyone(?) would use the terms in the way I (and many others) suggest.

Some rifles are called 'long throated' guns. Some of the Shiloh Sharps rifles made in Farmingdale, NY are so named. A 'long throated' rifle would be one with a very long, gentle taper to the leade, a longer than normal freebore, or both.
The 'Farmers' had a long freebore, for use with paper patched bullets.

Rifles can be chambered with no 'throat' at all. If the end of the rifling is at ninety degrees to the bore, and starts at the chamber step, there is no freebore or leade angle...therefore 'no throat'.
Actually, there are some who feel that a chamber with no freebore and a very abrupt leade angle (like 45 degrees) is a good candidate for paper patching when pullets patched to bore-diameter are used. Since the 'leade' is essentially an extension of the 45 degree chamber step, you could say there is no leade....along with no freebore...therefore 'no throat'.

A rifle with a short (or non-existent) freebore and a steep leade angle could logically be called a 'short throated' rifle. Current Shiloh Sharps chambers would fit that description, having a freebore only .05" long, and a five degree (included) leade angle.

The Postell bullet works very well in the 'short throated' Shiloh rifles. And now I am getting back to the actual topic of the thread..."bullet fit". The somewhat slender nose of the Postell slips into the bore diameter, and the first driving band fills the freebore (what there is of it) while it's rear half is still in the case mouth.
There is your two-point contact with barrel steel which holds the bullet in alignment with the bore before firing.

Compare that with the chamber found in the Pedersoli Sharps.
The freebore is .236" long and the leade angle is 1.5 degrees per side. The ogive on the PGT bullet was chosen to lay firmly in leade angle while a good portion of the nose is (almost) into the bore.
The nose is longer than the Postell. That spans the longer freebore to make rifling contact while the entire first driving band lays in the freebore.
Spec'd at a .460" diameter, the bullet also fills the diameter of the .460" freebore, leaving no room for 'modification' caused by bump up.

This is an example of how two (very similar) bullets are 'fitted' to two different throats to aid accuracy.

It is true that either bullet will perform well in either brand of rifle, but 'best' performance is more likely if each is used in a throat it truly 'fits'.

CM

Pat I.
02-01-2009, 04:56 PM
Charlie your terms are as good as any since there doesn't appear to be a consensus on what's right. I cut the throats in my barrels and make a taper die to match so the bullet fit's about as good as I'm gonna get with my limited smithing abilities. The angle of the leade is going to depend on the length of the bullet I plan on using and use 45 minutes for the long ones, 1 degree for the mid lengths, and 1 1/2 degrees for the shorter bullets, all included angles. I also cut a relatively to real, depending on bullet length, long freebore .0003 over bullet diameter to give the bullet as much guidance as possible.

I don't like having to depend on bore ride bullets so use LBT styles that can be tapered any way I want. It's basically the same as "bumping" but I come at it from the opposite direction. Fitting a bullet to a standard (?) throat is more voodoo and guess work than anything that could be pinned down and explained. Add a worn old military throat into the mix and things just get worse.

If I was going to suggest how someone fit a bullet I'd say. With a barrel using a free bore like the .308 find one with a nose as close to bore diameter as possible, slug the throat to get the diameter of the free bore, size your bullet so it's no more than a 1/2 thousandths under that measurement.

With a forcing cone style throat like on the 30-06. Again try to find a bullet where the nose matches the bore as close as possible and size it a couple thousandths over groove diameter so it hits the cone.

With something like the 30-30. Have someone cut a real throat in the thing and do one of the options above depending on how deep you run the reamer in.

If you're having a problem finding a bullet that'll cast with the right bore ride diameter go with a lighter shorter bullet with a shorter nose and longer body to act as guidance.

Just my $.002

joeb33050
02-02-2009, 08:15 AM
Maven got it - boolit diameter should be a fit for a fire formed neck.
Do you mean that the proper bullet diameter is that that just fits the fired case neck? If not, what do you mean?
For a particularly good shooting rifle, neck turning is a must. There after the correct boolit diameter can be determined but only after it has been fire formed after neck turned. This means that a case needs to fired at least twice in the process. Once to initially fire form, then neck size, trim and turn, then refire, then determine the boolit diameter.
Same question?
Maven's observation about seating depth is also noteworthy. Boolit base should be at the base of the neck. I've never heard this before, and have shot CBs with the base most anywhere in the case. My 30BR loads have a 314299 with just the GC in the case. Am I not understanding again?Then boolit length is determined to nose engraving or touching the lands. The rifle will tell you what boolits it likes as far as fit. Problem then is whether the twist and other conditions will support accuracy with a particular boolit.

44Man is right, too. Shoot it at the speed it is most accurate. The group of conditions that exist will determine the optimal velocity. Change any of the variables, and you start over.
Did I miss the point?
Thanks;
joe b.

Bret4207
02-02-2009, 12:37 PM
Those drawing are nice, but a pic of a chamber cast beside the drawing might help too. Drawings are fine, but don't always correlate to what a fellow might be looking at in his hand if he does a chamber cast.

Just a thought.

Pat I.
02-02-2009, 01:04 PM
If someone was writing this up for an article and got a good enough cast and had a good enough camera to take advantage of it a picture of a chamber cast would be a nice addition for visual effect, not volunteering here Joe. Personally though I'd trust a slug much more than a chamber cast for practical purposes.

joeb33050
02-02-2009, 06:46 PM
If someone was writing this up for an article and got a good enough cast and had a good enough camera to take advantage of it a picture of a chamber cast would be a nice addition for visual effect, not volunteering here Joe. Personally though I'd trust a slug much more than a chamber cast for practical purposes.
I guess that what I need is a few chamber drawings, 30-30 and a generic dwg with a ball seat and tapered throat. Without any names, no "throat" or "ball seat" or "leade", just drawings with dimensions.
Then it would be nice to have the same second dwg with all the choices, akin to the montana charlie dwg. All the words, looking like the article above with the three pictures.
I have a picture with 314299 and land engraving, but can't get it from my camera to the computer. I'm computer baffled about three times a day.
I have chamber slugs and sulfur cats of chambers, but no way now to get the camera working.
Here's one chamber swage picture.
This was intended to be simple, the way for the common shooter to approach the problem or question of bullet fit.
Maybe it can be done, but it ain't easy so far.
joe b.
joe b.

Bret4207
02-03-2009, 08:16 AM
If I was you Joe, what I would like is a picture like the one above(minus the glare- I believe there are photo programs that allow this work) with the specific areas labeled and measurements given along with a drawing and, if I had my way, the sectioned barrel that the slug came from. If someone can't see the idea from all that, better they take up knitting or stamp collecting!

joeb33050
02-03-2009, 01:01 PM
Involving a child got the camera and computer working together again. Here's a picture of a 314299 engraved by the lands-equally 0all around-though that can't be photographed.
The difference between the 314299 as shown and the 311299 not shown is ~ .002" on the nose, going from no engraving to engraving as shown. Thus, the engraving ain't deep.
Anybody want to make those chamber drawings?
Thanks;
joe b.

Tom Myers
02-03-2009, 02:05 PM
Involving a child got the camera and computer working together again. Here's a picture of a 314299 engraved by the lands-equally 0all around-though that can't be photographed.
The difference between the 314299 as shown and the 311299 not shown is ~ .002" on the nose, going from no engraving to engraving as shown. Thus, the engraving ain't deep.
Anybody want to make those chamber drawings?
Thanks;
joe b.

Joe,

If you can wait a couple or three days, I can give it a try. I have some computer repair work and software orders to fill then I should be able to focus on some drawings.

It might avoid confusion if you would make up sort of a list of the different aspects you would like displayed in each drawing, keeping in mind that the drawings can display all, or each, of either chamber, cartridge or bullet, individually or superimposed, one on another.

Respectfully,
Tom Myers
Precision Ballistics and Records (http://www.tmtpages.com)

joeb33050
02-04-2009, 07:10 AM
Tom;
I think what I need is 2 dwgs, 1 like a 308 or 30-06, with a free bore and a tapered leade; the other like a 30-30. Not to scale, so that the tapered leade shows up, and without any labels. These for the bullet fit article. It would be great to show a bullet in the chamber, a bore rider ex 314299 and then a non bore rider ex 31141.
Then I would take the first dwg and try to put ALL the labels/names on it, for the article on chambers and names of the various parts. Since there is little agreement about ball seat/free bore etc., I wrote the article telling what folks called the various parts of the chamber.
Is this understandable?
Thanks;
joe b.



Joe,

If you can wait a couple or three days, I can give it a try. I have some computer repair work and software orders to fill then I should be able to focus on some drawings.

It might avoid confusion if you would make up sort of a list of the different aspects you would like displayed in each drawing, keeping in mind that the drawings can display all, or each, of either chamber, cartridge or bullet, individually or superimposed, one on another.

Respectfully,
Tom Myers
Precision Ballistics and Records (http://www.tmtpages.com)

Tom Myers
02-04-2009, 10:45 AM
Tom;
I think what I need is 2 dwgs, 1 like a 308 or 30-06, with a free bore and a tapered leade; the other like a 30-30. Not to scale, so that the tapered leade shows up, and without any labels. These for the bullet fit article. It would be great to show a bullet in the chamber, a bore rider ex 314299 and then a non bore rider ex 31141.
Then I would take the first dwg and try to put ALL the labels/names on it, for the article on chambers and names of the various parts. Since there is little agreement about ball seat/free bore etc., I wrote the article telling what folks called the various parts of the chamber.
Is this understandable?
Thanks;
joe b.

Joe,

My drawings are all generated from software programs that I have developed. These programs obtain values from chamber, cartridge and bullet dimension database values. The images are all drawn to scale and labeled according to a programmed format.

I am not skilled at free style drawing so perhaps someone else would be better equipped to supply what you need.

However, If you can use material similar to the samples below, I'll do what I can to help.

Tom Myers
Precision Ballistics and Records (http://www.tmtpages.com)

http://www.tmtpages.com/LinkSkyImages/forum_images/Joe%20Brennam/308_Winchester_C.I.P.Standard~Barrel_50%25-Short.jpg

http://www.tmtpages.com/LinkSkyImages/forum_images/Joe%20Brennam/308_Winchester_C.I.P.Standard~Barrel_308_Wincheste r_C.I.P._Standard_Rot_Cutaway_Crimp_Ideal_Mold_308 291_Short-50%25.jpg
http://www.tmtpages.com/LinkSkyImages/forum_images/Joe%20Brennam/308_Winchester_C.I.P.Standard~Barrel-short.jpg

http://www.tmtpages.com/LinkSkyImages/forum_images/Joe%20Brennam/308_Winchester_C.I.P.Standard~Barrel_308_Wincheste r_C.I.P._Standard_Rot_Cutaway_Crimp_Ideal_Mold_308 291_Short.jpg

Beaverhunter2
02-04-2009, 01:04 PM
Great stuff, guys! Thanks!

John

44man
02-04-2009, 01:43 PM
That's what I call perfection! :drinks:

montana_charlie
02-04-2009, 01:46 PM
Those are nice pictures, Tom.
I will play with them to try to make an example of a 'long bore ride', and a 'short nose in the leade'.

See ya' later...
CM

It's later, now...

Here are two modifications of Tom's drawings.
The first has the bullet's nose stretched to show a typical long nosed bore rider sitting on the lands.

The second has the nose shortened and fattened a bit, to illustrate a bullet engaging 'the leade of the rifling' (which is labeled 'throat').

Both (still) show the second part of the 'two point contact' between lead and steel where the first driving band is firmly fitted in the freebore.

http://castboolits.gunloads.com/picture.php?albumid=88&pictureid=488
http://castboolits.gunloads.com/picture.php?albumid=88&pictureid=489

The amount of space between the end of the brass and the chamber step troubles me a little, but that's a subject for a different discussion. It's probably neccessary for bottlenecked cases and smokeless powders.

CM

ADDED...
Just for a comparative look at 'labeling', here is the bore rider modification from above...but the labeling has been changed to account for all elements within the 'throat' of the rifle's chamber.

When used in this way all of the terms have an identifiable meaning...and none conflict with the others.
As illustrated, 'throat' can be defined as, "The distance from the chamber to the point where the lands reach bore diameter."

http://castboolits.gunloads.com/picture.php?albumid=88&pictureid=490

joeb33050
02-04-2009, 04:49 PM
These drawings look great to me, except for the crimp in the case. What is the "two point contact" that is mentioned, where are the two points?
Let me think for a bit.
Thanks;
joe b.

carpetman
02-04-2009, 05:01 PM
darn---Thought this thread was going to be about Linda Lovelace

montana_charlie
02-04-2009, 05:49 PM
What is the "two point contact" that is mentioned, where are the two points?
Joe,
Take the drawing with the long bore rider as an example.
The first driving band is filling the freebore, so that is one point where the lead is firmly supported by steel. Then note that the nose is held snugly in the lands. That is the second point of contact.

Because they exist, they hold the bullet in alignment with the center of the bore.
That is what you want from a 'well fitted' bullet...one dimensioned for the throat you plan to shoot it in.

If the driving band was not there (or was smaller than the freebore), you can see the bullet would have to depend on the cartridge case to center up the rear end. But, the brass does not completely fill the chamber cut (there has to be some space there for expansion to release the bullet).
So, the bullet could drop down a few thousandths (in the rear) if the rest of the case body was as as loose in the chamber as the neck is.
That would constitute a misalignment between the bullet and the bore.

On the other end, if the bore ride section was smaller than bore diameter, the bullet could tilt (or, it could 'slump') up, down, or sideways when fired.

CM

Tom Myers
02-04-2009, 08:06 PM
ADDED...
Just for a comparative look at 'labeling', here is the bore rider modification from above...but the labeling has been changed to account for all elements within the 'throat' of the rifle's chamber.

When used in this way all of the terms have an identifiable meaning...and none conflict with the others.
As illustrated, 'throat' can be defined as, "The distance from the chamber to the point where the lands reach bore diameter."


CM,

You have it right. I like it.
I'll put on my programmers hat and see if I can make all the different configurations come out with that format.
Thanks,
Tom

P.S.
The reason the brass does not reach to the end of the chamber is because the C.I.P. Standard specs values were entered as published and that is the way it is displayed. If I were to set up a load, I would have the brass trimmed to within at least 0.005" of the end of the chamber. In my BPCR 40-65, I trim the brass to as close to zero gap as I can. It dramatically limits throat leading.

Pat I.
02-04-2009, 08:45 PM
I for one would like to say thanks to both Tom and MC. You've both done an excellent job of explaining a hard to explain subject. A visual aid goes a long way. MC I'd like to know how you stretched and shrunk that bullet though.

montana_charlie
02-04-2009, 10:28 PM
MC I'd like to know how you stretched and shrunk that bullet though.
Can you spell ******? Can you spell it backward?

Seriously...
Microsoft Paint is the only graphics software I am smart enough to use. After many hours of dinking with it (while drawing up stuff for the 'case stretcher project') I figured out how to manipulate stuff...as long as somebody else supplies the stuff for me to manipulate.

Basically, I use 'cut, copy and paste', as well as the 'select' and 'move' features of the software, to reposition portions of the image...to make things look as I want them to.

It's almost impossible to explain how to do it...but anybody should be able to figure it out by just messing with it.


In my BPCR 40-65, I trim the brass to as close to zero gap as I can. It dramatically limits throat leading.
And that's EXACTLY why I invented the Kal-Max Case Stretching Jig with the able assistance of Rick Kalynuik, who does such a masterful job of building them.

CM

Ricochet
02-04-2009, 10:56 PM
Can you spell ******? Can you spell it backward?
OOOOH, you wouldn't want to take Argaiv by mistake!

joeb33050
02-06-2009, 08:22 AM
I understand this about bore riders. Other bullets, like 31141 and 311291 and Loverin styles are non bore riders. For these, I make the bullet as big in diameter as will go in the free bore, and OAL such that there is a mash against the rifling or leade. I think that these shoot well because the bore filling length is long enough to keep the bullet straight. Sort of like a Pope tapered, though not much, bullet.
Is this what you do/think?
Thanks;
joe b.




Joe,
Take the drawing with the long bore rider as an example.
The first driving band is filling the freebore, so that is one point where the lead is firmly supported by steel. Then note that the nose is held snugly in the lands. That is the second point of contact.

Because they exist, they hold the bullet in alignment with the center of the bore.
That is what you want from a 'well fitted' bullet...one dimensioned for the throat you plan to shoot it in.

If the driving band was not there (or was smaller than the freebore), you can see the bullet would have to depend on the cartridge case to center up the rear end. But, the brass does not completely fill the chamber cut (there has to be some space there for expansion to release the bullet).
So, the bullet could drop down a few thousandths (in the rear) if the rest of the case body was as as loose in the chamber as the neck is.
That would constitute a misalignment between the bullet and the bore.

On the other end, if the bore ride section was smaller than bore diameter, the bullet could tilt (or, it could 'slump') up, down, or sideways when fired.

CM

Ricochet
02-06-2009, 12:02 PM
I believe #311291 is a bore rider, just one with a fairly short bore riding section.

joeb33050
02-06-2009, 12:12 PM
I believe #311291 is a bore rider, just one with a fairly short bore riding section.
The bore riding 311291 is rare, about as rare as the unicorn. Mine, unlike myself, have and had small noses. Rarely, after drinking to excess, I've seen one where the nose is big enough to ride. Sober, none are to be found.
joe b.

Pat I.
02-06-2009, 12:20 PM
I'd say the term bore rider is a design not an actual fact. I've had a lot of moulds that were considered bore riders with undersized noses. You're splitting hairs here Joe.

montana_charlie
02-06-2009, 01:01 PM
I make the bullet as big in diameter as will go in the free bore, and OAL such that there is a mash against the rifling or leade.
Is this what you do/think?
You have two points of contact. One is the nose wedged into the leade, and the other is the driving band filling the freebore.
They are not very apart, so the bullet doesn't have much 'leverage' for holding the case up off the bottom of the chamber. A fireformed case dimension would probably be helpful in that regard.
CM

montana_charlie
02-06-2009, 01:12 PM
I'd say the term bore rider is a design not an actual fact. I've had a lot of moulds that were considered bore riders with undersized noses. You're splitting hairs here Joe.
The aim of the thread is to explore the value of 'throat fit' as it relates to why a well-fitted bullet is desirable. It assumes that a properly dimensioned bullet is available, and asks why it is beneficial to use it.
The other side of the coin is...why buy a custom mould if the same design is available from Lee, Lyman, etcetera?

Any bore rider nose that does not match bore diameter is not a 'well-fitted' bullet.
It is the product of a mass produced mould which just adheres to the outline of a particular design, but does not actually 'fit' (unless by accident) the individual rifle in question.

Similarly, a custom-made mould cut for somebody else's rifle may be a poor fit in yours.

CM

Pat I.
02-06-2009, 02:36 PM
Not disagreeing and I understand the topic is about bullet fit. The point of my post was to point out to Joe that just because the nose of a bore ride bullet might be too small to make contact with the bore in your rifle doesn't mean it's not a bore ride design and I'd have to say that the 291 is a bore ride bullet. Might be a short bore ride design and too small to fit some individual barrels but bore ride none the less.

Larry Gibson
02-06-2009, 03:03 PM
Got to disagree with the drawing. It is nicely done but the "throat" and "freebore" are synonimus and essentially the same. On the drawing what is called "throat' is actually the "leade".

Larry Gibson

montana_charlie
02-06-2009, 05:04 PM
Got to disagree with the drawing. It is nicely done but the "throat" and "freebore" are synonimus and essentially the same.
There are many who subscribe to that school of thought, Larry, that 'throat' and 'freebore' mean the same thing.

On the drawing what is called "throat' is actually the "leade".
Uhh...which drawing are you referring to...the last one?
You'll notice that the last one has three different lengths listed for the three different terms...
CM

Larry Gibson
02-06-2009, 06:25 PM
There are many who subscribe to that school of thought, Larry, that 'throat' and 'freebore' mean the same thing.

Uhh...which drawing are you referring to...the last one?
You'll notice that the last one has three different lengths listed for the three different terms...
CM

Ooops! Apparently my computer was slow downloading and I only saw the first two pictures. The third one is correct with "throat" and "freebore" being interchangeable and the "leade" being correct.

Larry Gibson

montana_charlie
02-06-2009, 07:38 PM
The third one is correct with "throat" and "freebore" being interchangeable and the "leade" being correct.
In that iteration, the freebore is shown with a length of .114", while the length dimension for the throat is .245". Do you find using 'throat' to describe the combined length of the freebore and leade to be totally unacceptable?

If so, what term would you use to name 'the distance from the chamber to the point where the lands have risen to bore diameter' ?

CM

felix
02-06-2009, 08:16 PM
Might be, Larry, but I like the throat to mean freebore + leade, just like CM/MC says. ... felix

felix
02-06-2009, 08:22 PM
Chamber in my mind is the whole ball of wax: head,body,bottleneck,neck,freebore,leade. ... felix

Tom Myers
02-06-2009, 11:05 PM
I to re-wrote the code in the Chamber Drawing module to more clearly define the area from the end of the chamber to the point where the leade becomes bore diameter.

The length of the step down from the chamber mouth is included in the Throat Length as in some cases there is no step as the Leade is started right at the case mouth and is a straight cone to bore diameter.

If the bore ride section is a larger diameter than the groove diameter, then the throating reamer cuts a taper down to the groove diameter that has no lands or grooves . It can be describes as the "Frustum of a Cone" but I just call it the "Free bore Angle" and consider it as part of the leade. But it still must be accounted for when designing a fitted bullet so it is marked as "Freebore > L." (Free bore Angle Length)

My 40-65 Ron Long chamber was cut with a free bore that is 0.002" over groove size so a portion of the free bore length is also the beginning of the 5 degree included angle leade.

I also re-wrote the code in the Composite module to display only a portion of the length of the overlays so as not to stretch the forum posts excessively.

The first image shows the dimensions of the chamber at 2000 pixels per inch.

The second one displays a bullet I designed to fit the chamber/ throat area. and the rest show different views of the chamber case bullet combinations. The front band is 0.001" less than the free bore and tapers down to the start of the ogive at a 2.5 degree per-side angle

One thing I try to do when loading that cartridge is to place a grease groove right at the end of the chamber so that when the fire is lit behind the bullet, lube is forced into the gap between the case and chamber mouth. That way, the ring that I get on the end of a fired case is lube and not lead.

http://www.tmtpages.com/LinkSkyImages/forum_images/ChamberSpecs/Throat%20Fit/40-65-RonLong%20Throat%20x%202000.jpg

http://www.tmtpages.com/LinkSkyImages/forum_images/ChamberSpecs/Throat%20Fit/A_TMT_Design_40-65_RL_427_gr_Sketch.Jpg

http://www.tmtpages.com/LinkSkyImages/forum_images/ChamberSpecs/Throat%20Fit/40-65_Win_Ron_Long_Ron_Long~Barrel_40-65_Win_Ron_Long_W-W_Rot_Cutaway_A_TMT_Design_40-65_RL_Rot.Jpg

http://www.tmtpages.com/LinkSkyImages/forum_images/ChamberSpecs/Throat%20Fit/40-65_Win_Ron_Long_Ron~Long_Barrel_500_40-65_Win_Ron_Long_W-W_Rot_Cutaway-50%25_A_TMT_Design_40-65_RL_Rot-50%25.Jpg

Larry Gibson
02-06-2009, 11:15 PM
Might be, Larry, but I like the throat to mean freebore + leade, just like CM/MC says. ... felix

felix

I can understand that and I many times refer to them as such also. However, technically speaking they are, in fact, two seperate things. As such each should have it's own specific name. Otherwise how could we seperate out the requirement for the degree of taper the "leade" should have from the diameter of the throat to the top of the lands vs the diameter the "throat" should have in the first place?

Larry Gibson

felix
02-06-2009, 11:28 PM
You can't, Larry, and that is why a picture like above is required. Just like Mike of Colorado gets bent out of shape over the term headspace. His definition is correct like yours is, but what everyone thinks it is changes the definition. That's the beauty of the French language and why the world court uses it. There are about 10 definitions of love, while in English only a few. Latin, the most concrete of languages, is typically used for the purpose of exactness because there is only one emphatic meaning per word. ... felix

montana_charlie
02-06-2009, 11:58 PM
However, technically speaking they are, in fact, two seperate things. As such each should have it's own specific name.
The polite thing to say right here is, "Larry, you lost me." But the fact is, Larry, it is you who are lost in this particular discussion.

Now, before you get mad, just let me show you how this works out for each feature to have it's own unique name.

At the end of the chamber cut is a cylindrical zone which has no rifling cut in it. It's usually a straight cylinder, or it might have some taper...but is bored out free of rifling.
Call it the 'freebore'.

At the end of the freebore is a zone which has the rifling lands starting to ramp up to bore diameter. It might be a steep angle, or a gentle one...but it eventually becomes the full height rifling.
Call it the 'leade'.

So, you have two, separate, features...each with it's own specific name as you said is necessary.

I know you're still with me up to this point...

Now take the freebore's length (whatever that happens to be) and add it to the length of the leade...and call that zone (which is a combination of the freebore and leade)...call it 'something'.
You know, give that 'overall zone' it's own specific name just like the other two zones.
What if you called it the throat? This throat has two 'things' in it, a freebore and a leade...just like your own throat (the one between your chin and your chest) has both a trachea, and an esophagus.

It makes good sense when you consider that if...
1 + 2 = 3

and...

A + B = C

why can't...

Freebore + Leade = Throat

so that...

Freebore length + Leade length = Throat length



Otherwise how could we seperate out the requirement for the degree of taper the "leade" should have from the diameter of the throat to the top of the lands vs the diameter the "throat" should have in the first place?
Did the explanation above answer this question when you consider that freebore length and diameter is one element...and leade angle and length is another element...making 'throat' a good term to describe the combination of (any and all) elements that exist between the chamber cut and the full height rifling?

CM

felix
02-07-2009, 12:13 AM
It is much more clear, Larry. Now, we have to make the case area more clear. Be my guest, CM. ... felix

montana_charlie
02-07-2009, 12:58 AM
Now, we have to make the case area more clear. Be my guest, CM. ... felix
I'm not real sure what you just invited me to do, Felix.

To me, the case area (or the zone which contains the case) is 'the chamber'.
The zone in front of 'the chamber' may include both a 'freebore' and a 'leade', or maybe just one or the other.
An all-inclusive term for everything that does exist in that zone is 'the throat'.
So, 'the chamber' is connected to 'the bore' by 'the throat'.
And all of them together (along with 'the bore') make up a zone described by another all-inclusive term...'the barrel'.

To me, all of this is so simple, it's child's play.
Whoever it was (way back when) who started the process of scrambling the meanings of these terms must have been a bamboozling lawyer...or it came from confusing rifle-talk with revolver-speak.

CM

Cap'n Morgan
02-07-2009, 04:26 AM
To me, all of this is so simple, it's child's play.
Whoever it was (way back when) who started the process of scrambling the meanings of these terms must have been a bamboozling lawyer...or it came from confusing rifle-talk with revolver-speak.

The step between neck and freebore - is it a part of the chamber, or the throat? Inquiring minds want to know [smilie=1:

joeb33050
02-07-2009, 07:05 AM
While it is interesting to some, the definition or word meaning elements of the discussion are of little to no value. There is no universally acceptable definition of the words "headspace", "throat", "leade", etc.; hence the article that I wrote, with the help of several CBA forum guys, that is posted above, that shows the various meanings of the various words. If there is anything missing or incorrect in that article I'd like to know and fix it.
I need some drawings of the bullets in cases for the article, without the crimp-which for accuracy purposes we leave off. Would you...........?
Thanks;
joe b.

joeb33050
02-07-2009, 07:12 AM
Not disagreeing and I understand the topic is about bullet fit. The point of my post was to point out to Joe that just because the nose of a bore ride bullet might be too small to make contact with the bore in your rifle doesn't mean it's not a bore ride design and I'd have to say that the 291 is a bore ride bullet. Might be a short bore ride design and too small to fit some individual barrels but bore ride none the less.
Pat;
Call it what you want, Obama and I support your right to free speech.
joe b.

joeb33050
02-07-2009, 07:46 AM
You can't, Larry, and that is why a picture like above is required. Just like Mike of Colorado gets bent out of shape over the term headspace. His definition is correct like yours is, but what everyone thinks it is changes the definition. That's the beauty of the French language and why the world court uses it. There are about 10 definitions of love, while in English only a few. Latin, the most concrete of languages, is typically used for the purpose of exactness because there is only one emphatic meaning per word. ... felix
The official languages of the World Court are English and French.
Latin, "cancer" means a crab, the direction south, the heat of summer, and the disease.(It's always good to check up on Felix.)
joe b.

Tom Myers
02-07-2009, 08:02 AM
I need some drawings of the bullets in cases for the article, without the crimp-which for accuracy purposes we leave off. Would you...........?
Thanks;
joe b.

Joe,

Do you want chamber drawings with the bullets in the cases or do you want just the casing and seated bullet drawings? vertical? horizontal? Dimensons? Sectioned?

Tom Myers
Precision Ballistics and Records (http://www.tmtpages.com)

joeb33050
02-07-2009, 08:30 AM
Joe,

Do you want chamber drawings with the bullets in the cases or do you want just the casing and seated bullet drawings? vertical? horizontal? Dimensons? Sectioned?

Tom Myers
Precision Ballistics and Records (http://www.tmtpages.com)
Tom;
For the "bullet throat fit" article, I think I need
a 30-30 type chamber drawing (with no throat or leade), dimensioned, horizontal
a 308 type chamber drawing dimensioned, horizontal

The drawings that you made would be fine, but that they are so big that reducing the size makes the writing/dimensions get too small.

a bore ride bullet drawing, dimensioned, horizontal
a non bore ride bullet drawing, dimensioned, horizontal

Then, and I know I'm asking a lot, drawings of each bullet in each case showing what they fit, the throat bullet fit which we're after here.

Then, for the explanation of the various meanings of the words, a drawing of a chamber showing what the word meanings are to different people. So part would be labeled both "ball seat" and "free bore", etc. This word meaning business confuses some and infuriates others-the article I put above was intended to clear this up, but as Pat points out, the drawings aren't clear.

Thanks;
joe b.

Pat I.
02-07-2009, 08:59 AM
It's not what I want to call it Joe it tis what it tis.

Larry Gibson
02-07-2009, 12:43 PM
You can't, Larry, and that is why a picture like above is required. Just like Mike of Colorado gets bent out of shape over the term headspace. His definition is correct like yours is, but what everyone thinks it is changes the definition. That's the beauty of the French language and why the world court uses it. There are about 10 definitions of love, while in English only a few. Latin, the most concrete of languages, is typically used for the purpose of exactness because there is only one emphatic meaning per word. ... felix

felix

That's probably why science uses Latin instead of French. It's matter of whether you want to be specific or talk in generalities. Many of us prefer to talk of specifics and facts. Many prefer generalities, opinions or myths. Most are in the middle and confused, I wonder why........

Larry Gibson

Larry Gibson
02-07-2009, 12:54 PM
montana charlie

"What if you called it the throat? This throat has two 'things' in it, a freebore and a leade...just like your own throat (the one between your chin and your chest) has both a trachea, and an esophagus."

Sorry, but that definition does not fit unless you want to have "except for this and except for that......think about it. How many "throats in a revolver cylinder have "leades" in them? None is the answer so unless you make an "exception" to your definition it is not valid. Think about it. The throat and freebore are synonimus but the leade is a different thing. If you are going to call your "zone" in a rifle chamber something do so, but technically it encompasses the throat and the leade. Those are two seperate things and have two seperated definitions. I am not "lost in this particular discussion".

I am simply advising rewriting definitions for the sake of opinions which only further confuse the masses. These areas of the cahmber were defined correctly long ago. Is there a real need to redefine and change them? I think not. When Joe started this thread the question was "the bullet must fit the throat". The throat is clearly defined and has been for some time. We should not change it.

Larry Gibson

Larry Gibson
02-07-2009, 01:00 PM
The step between neck and freebore - is it a part of the chamber, or the throat? Inquiring minds want to know [smilie=1:

That is the "mouth" of the chamber just like the case has a "mouth". Appears CM doesn't understand felix's question so to get him started the chamber would consist of the body, shoulder (if there is one), neck, chamber mouth, etc.......each with it's own distictive and technically correct definition. All of which combined are part of the "chamber" as CM mentions. The throat and leade are not a seperate "zone" but also simply distictive parts of the "chamber".

Larry Gibson

Larry Gibson
02-07-2009, 01:06 PM
While it is interesting to some, the definition or word meaning elements of the discussion are of little to no value. There is no universally acceptable definition of the words "headspace", "throat", "leade", etc.; .........
joe b.

Joe

This is not true at all. There are indeed universal acceptable definitions of chamber componants out there. They are industry standard for CIP, SAAMI and I'm sure the COM-BLOC nations. Otherwise specifications could not be uniform enough for mass production and established specifications. It is only through forum discussions such as these that opinion seems to have more validity than fact. Check the proper places, there are indeed definitive definitions.

Larry Gibson

Larry Gibson
02-07-2009, 01:19 PM
Joe

"Then, for the explanation of the various meanings of the words, a drawing of a chamber showing what the word meanings are to different people. So part would be labeled both "ball seat" and "free bore", etc. This word meaning business confuses some and infuriates others-the article I put above was intended to clear this up, but as Pat points out, the drawings aren't clear."

That is just the problem, putting the multitude of different (most often incorrect) names for each part of the chamber only detracts from the quality of your article. For example; let's call the chamber a "recptacal", the cartridge a container and the barrel the exhaust pipe. Does that make sense? Of course it doesn't.

Joe, if you can't get the definitions correct how do you expect anyone to take the rest as correct? If you want to publish an encyclopedia of "commonly used firearm terms" then do that. If you want to publish something factual then be factual. Otherwise those that know and those that learn will quickly dismiss your work.

I am trying to be supportive here. Your original concept of this article and the previous was to keep it simple for the cast bullet shooter starting out to load acceptable cast bullet loads. I see you accepting too much opinion and trying to include 'everything". My advise is keep to the basics of your concept and be technically correct. Your basic concept for these articles is a very good one, stick with it. Do not put everyone's opinion in your article. "Everything" is not "basic". Anyone who knows the correct defintions and sees incorrect ones or a conglomeration of them to keep everyone happy will suspect the rest of the article. After all, if the definitions aren't correct how can we know the rest is? Your article will not be referred to novices because of this. It happens all the time with written works with errors in them.

Larry Gibson

montana_charlie
02-07-2009, 01:53 PM
The step between neck and freebore - is it a part of the chamber, or the throat? Inquiring minds want to know.
I would just say that is the end of 'the chamber''. It is usually cut at an angle, but it could be a straight-up 90 degree end...depending on the shape of the reamer.

I have said my piece on the subject of this thread.
Thanks to those with open minds, and 'peace' to any old dogs who can't learn new tricks...
CM

joeb33050
02-07-2009, 05:07 PM
Joe

This is not true at all. There are indeed universal acceptable definitions of chamber componants out there. They are industry standard for CIP, SAAMI
I don't know about CIP. Look it up, the old com bloc nations are well represented. But SAAMI makes it clear that the definitions that they use are only that, the definitions that they use.
look it up.
I find that there is no close-to-universally accepted definition for these words, hence the explanation in the article I wrote months ago, maybe years ago.
I'm not saying it's right, or that I don't wish that improper speakers or writers shouldn't be flogged. I just write what is.

and I'm sure the COM-BLOC nations. Otherwise specifications could not be uniform enough for mass production and established specifications. It is only through forum discussions such as these that opinion seems to have more validity than fact. Check the proper places, there are indeed definitive definitions.

Larry Gibson
Why am I doing this?
joe b.

joeb33050
02-07-2009, 05:14 PM
Joe

"Then, for the explanation of the various meanings of the words, a drawing of a chamber showing what the word meanings are to different people. So part would be labeled both "ball seat" and "free bore", etc. This word meaning business confuses some and infuriates others-the article I put above was intended to clear this up, but as Pat points out, the drawings aren't clear."

That is just the problem, putting the multitude of different (most often incorrect) names for each part of the chamber only detracts from the quality of your article. For example; let's call the chamber a "recptacal", the cartridge a container and the barrel the exhaust pipe. Does that make sense? Of course it doesn't.

Joe, if you can't get the definitions correct how do you expect anyone to take the rest as correct?
This is my last reply about word meanings.
I found this today, written by a well known and respected gun writer.

" This directly affects "headspace," a technical term for the tiny gap between bolt-face and cartridge-head after a round's chambered. "

Some words have different meanings to different people. That is the way the world, and people, work. Getting tense about it is, in my opinion, not worth the bother.







If you want to publish an encyclopedia of "commonly used firearm terms" then do that. If you want to publish something factual then be factual. Otherwise those that know and those that learn will quickly dismiss your work.

I am trying to be supportive here. Your original concept of this article and the previous was to keep it simple for the cast bullet shooter starting out to load acceptable cast bullet loads. I see you accepting too much opinion and trying to include 'everything". My advise is keep to the basics of your concept and be technically correct. Your basic concept for these articles is a very good one, stick with it. Do not put everyone's opinion in your article. "Everything" is not "basic". Anyone who knows the correct defintions and sees incorrect ones or a conglomeration of them to keep everyone happy will suspect the rest of the article. After all, if the definitions aren't correct how can we know the rest is? Your article will not be referred to novices because of this. It happens all the time with written works with errors in them.

Larry Gibson
So much for linguistics.
joe b.

Larry Gibson
02-07-2009, 05:41 PM
Guess I won't bother any more either if you don't care. Call them what you will.

BTW; That "well known and respected gun writer" (to many that is a contradiction of terms) has that definition wrong. Were I and many others to read that the writer would be less respected and only well known for his inaccuracies. I was hoping that wasn't the type of writer you seeked to emulate.

Larry Gibson

Tom Myers
02-07-2009, 06:06 PM
For what it's worth, I found these definitions on the SAMMI website.

"..........It is, in other words, a working draft that, it is hoped, may be useful in addressing certain technical matters frequently considered by the Technical Committee and is subject to further change and refinement.."

CHAMBER:
1. In a rifle, shotgun or pistol, the rearmost part of the barrel that has been formed to accept a specific cartridge or shell when inserted.
2. In a revolver, the holes in the cylinder that have been formed to accept a cartridge .

BALL SEAT: See Leade.

THROAT : See Leade (Lead).

FREE BORE:
A cylindrical length of bore in a firearm just forward of the chamber in which rifling is not present. Associated with bullet jump.
BULLET JUMP:
The distance that a bullet must travel from its position at rest in the cartridge case to its initial engagement of the rifling.

LEADE (LEAD):
That section of the bore of a rifled gun barrel located immediately ahead of the chamber in which the rifling is conically removed to provide clearance for the seated bullet. Also called Throat or Ball Seat.

LAND, LANDS The uncut surface of the bore of a rifled barrel.

BORE The interior of a barrel forward of the chamber.

BORE DIAMETER
1. Rifled barrels: the minor interior diameter of a barrel which is the diameter of a circle formed by the tops of the lands.
2. Shotguns or muskets, the interior dimension of the barrel forward of the chamber but before any restrictive choke or expanded muzzle.

GROOVES See Rifling.

GROOVE DIAMETER The major diameter in a barrel which is the diameter of a circle circumscribed by the bottom of the grooves in a rifled barrel.

RIFLING Grooves formed in the bore of firearm barrel to impart rotary motion to a projectile.

Pat I.
02-07-2009, 07:35 PM
Well Tom I guess that puts this argument to rest. :-D

How about "Straight Part", "Tapered Part" and "Whole Thing" since like has been said, there ain't no standard terminolgy.

trk
02-07-2009, 07:45 PM
OR, if one uses a non-standard term, USE A DRAWING with the area in question identified!

As: diameter between point A and point B.

Did I actually make another comment on a well beaten to death topic? Sorry. :-)

45r
02-10-2009, 03:08 PM
A perfect fit of the drive band into the lead and light crush fit on the bore-rider on my mtn mold boolits shoot very well on my micro-groove 35 rem Marlin.I fire-lapped the barrel till the fit was perfect and the rifle shoots bug hole groups and no leading at all.I didn't think the shallow rifling would shoot so well but I guess that a perfect fit and smooth bore is the most important part of accuracy.I didn't even have to water quench the boolits.

runfiverun
02-11-2009, 01:21 AM
i have been calling the various parts of the leade by the correct names but apparently referring to them in the wrong position.

joe: i would just draw/print the picture with labels like this....
/..leade/..../freebore/... etc so that at least the proper order is established and they can see what you are talking about...
nice to see though, that i don't know the proper terms i can splain what you need to know to make things fit correctly.

joeb33050
03-09-2009, 07:19 AM
May I use the drawings above in the book?
Thanks;
joe b.

joeb33050
04-06-2009, 07:28 AM
To test the no-chamber-cast-no-bore-slugging-just-mash-them-in procedure, I borrowed a rifle in 308 Win. This is a WWII Mauser action, ?Timney? trigger, heavy 26" barrel, carved stock, Lyman 48 rifle built by Creighton Audette, a long time ago. I found it in a gun shop ~20-25 years ago, had no interest, my friend bought it.

I loaded 314299 and 31141 with 15/A#9 and WLR primers, a load below starting, charge out of the Lyman 49th handloading.
The scope blocks are way off, with 30X Lyman STS bottomed out the bullets hit 9-10 inches high at 100 yards.
5 shot groups
31141, 2.3", 1.4", 1.55", 1.7", 1.6"; 1.71" average.

314299, 1.7", 2.0, 1.5", .825", 1.3"; 1.465" average.

Ordered a new scope block from Steve Earle.
(I used A#9 because I like it; however 5744 or IMR4227 or other powders would do the same.)
joe b.

runfiverun
04-07-2009, 04:35 PM
see....
take the 299 and play with it some, and you will hit 1" groups soon enough.
it ain't all that hard.
[smilie=b:

joeb33050
04-09-2009, 11:38 AM
Yesterday, 314299, 201.7-202.2 gr.,WLR, 5 five shot groups, 100 yards, Creighton Audette Mauser 308 Win.

16/ A#9
Clean, .95", 1.5", 2.75", clean, 1.25", 2.3" avg. 1.75"

17/A#9
Clean, 1.1", 1.55", clean, 1.2", 2.35", clean,1.3", avg. 1.50"

Never slugged the bore, chamber cast, measured much of anything.
I think I'm having a lube problem, I've asked for 2 sticks of lube for the 450.
joe b.

goofyoldfart
03-06-2011, 05:18 AM
CM : your definitions w/the pictures really cleared up a lot of questions in my mind. when I read Larry's articles or posts, I expect to get a highly technical article and I do enjoy them for that reason. But there are times that I do enjoy some simplicity and this was one of them. the explanations did help. Larry, how shall we say this, that sometimes when you're trying to present an Idea for clarification--well....you do get a slight bit caustic in your explanations. Now please don't take the wrong impression that I am trying to flame you, because I DO enjoy many of your posts due to the knowledge gleaned. you seem to have a logical progression of from point "A" to point "B" to point "C". I just feel that sometimes you feel that your feelings and intelligence are being ridiculed. Hey, friend, just take a deep breath, relax and have a little chuckle. We all are in this together. God Bless to all.

The Goofyoldfart AKA GOF or Goofy:bigsmyl2::cbpour::redneck:

montana_charlie
03-06-2011, 12:31 PM
I'm glad you like simplicity as much as I do, Goofy. Larry does not.
CM

SgtDog0311
11-15-2015, 12:24 PM
This is an old one but I have nothing but appreciation for threads like this! Thanks!!

I wonder if anyone has ever designed a chamber with a step down at the case neck, say something like a 12* (something less abrupt than a 45* would be my preference), into a freebore that was funnelled with a 4* taper to the groove diameter.

For example, a 40-65 with a .408 groove that would accept a .409 or .410 and had a swaging freebore that went from .410 at the start of whatever step for the case mount a fellah selected to the .408 groove diameter.

Probably need reduced driving bands in that case but seems like it would be halfway between the recommendation for a fully supported freebore and those who might want some swaging characteristic in their throat.

If I had Tom's software mastered I'd draw it just to see it but I don't. Hope to get there someday.

montana_charlie
11-15-2015, 05:37 PM
Yes, people have cut chambers with low angles in the step and leade areas.
One shape popular with paper patch shooters has an angle of (about) six degrees which tapers from the chamber diameter (bullet diam. + wall thickness doubled) down to bore diameter in a single cone shaped cut.

This is possible when making a new barrel, where there is no existing internal 'topography' that must be erased.
When there is a leade, then the six degree taper goes until it contacts that leade angle ... creating a compound angled throat ... but still providing a 'gentle' path for the paper patch to ride.

SgtDog0311
11-15-2015, 05:58 PM
Ha... Now that I look at post # 42 it looks like MC's second 308 diagram does something similar with the freebore1 and freebore2.

My first thought there would be to question how that would work in a BPCR rifle where bullets are sometimes seated out for greater capacity or for whatever reason. Looks like reduced driving bands WOULD be required there else you'd have resistance in chambering with the first full-diameter driving band being swaged in “tapered freebore” (recognizing of course I may be using another controversial term J). That is if a shooter found himself wanting to seat the bullet further out.

Probably mostly talking to myself here since I could fit 44man’s post #14 description.
Ha... Now that I look at post # 42 it looks like MC's second 308 diagram does something similar with the freebore1 and freebore2.

My first thought there would be to question how that would work in a BPCR rifle where bullets are sometimes seated out for greater capacity or for whatever reason. Looks like reduced driving bands WOULD be required there else you'd have resistance in chambering with the first full-diameter driving band being swaged in “tapered freebore” (recognizing of course I may be using another controversial term J). That is if a shooter found himself wanting to seat the bullet further out.

Probably mostly talking to myself here since I could fit 44man’s post #14 description.

SgtDog0311
11-15-2015, 06:19 PM
CM, was typing while you commented. Thanks!

It's the step down from case to freebore diameter I hadn't seen combined with a funnel transition in the 40-65 reamer diagrams I've inspected. Usually they step down 45* to a cylindrical freebore, else they start the taper at the end of case mouth without any step, just a direct line from case mouth diameter to groove diameter, one straight line. Or they may show no freebore at all. So far, of the Clymer, Browning, Winchester, Ron Long and some casts are all I've seen.