Sizing a Boolit, makes it less accurate ?

[JonB_in_Glencoe]

This is a quote from page 41 of the RCBS cast bullet manual #1

Effect of Sizing
Experience has shown that each .001" of sizing results in about an extra inch of group dispersion at 100 yards. And don't think your barrel can size any better than your sizer/lubricator. It can't. The bullets must be perfect out of the mould.

I posted this in another thread to clarify that RCBS molds have 'tight specs' and don't cast oversize. I have beening thinking about this since then...and I find it hard to believe the 1" of Dispersion at 100 yards for every .001" of sizing, but I am no expert, and have done NO tests to contradict this statement.

Is anyone else skeptical of this as well ?
Jon

[cajun shooter]

I have been casting since 1970 and I have purchased lots of RCBS moulds.
For RCBS to make such a blanket statement is a mistake. There are too many variables in casting such as alloy used being the largest to warped blocks that produce out of round bullets.
As a general rule your cast bullet should be .001 larger than the bore of the gun it is fired from. I have owned many different brands and types of guns and they all have a certain preference for a certain size of bullet.
My S&W model 27 shot best with .358 bullets with a .357 bore. My Colt shot best with a .454 bullet and a .4525 bore.
I currently shoot the 44-40 caliber with 100% black powder and bullets that are sized and lubed at .429 and the rifle and revolvers have bores of .427.
Things such as powder used, amounts used, type of targets, and distance all come to mind.
I say this as being my experience and not that it is anything that is a standard for others to do.
I also would like to see the entire article that your quote came from as we may be in the wrong building all together.

[gnoahhh]

I like a bullet to pop out of the mold at the dimensions ideally suited to the barrel they will be used in. NOT that that happens too often, and usually it means a trip down the custom mold path! When that state of nirvana happily happens, I use the sizer merely to lube and seat gc's. The more perfect the bullet is from the mold, and the less one has to size it, the better off you are IMO. In a perfect world, all sizers are perfectly true and don't produce unevenly sized bullets. In a perfect world.

[ku4hx]

Firing a boolit makes it less accurate considering all the stresses it undergoes before it even leaves the barrel!

Cast 'em, size 'em if necessary, lube 'em the best you know how and then shoot 'em and have a good time.

[243winxb]

Lyman has said to not size down more that .003" to retain accuracy. Old NRA reprint on the 45 acp has shown less sizing is better. This is how i remember it.

[geargnasher]

Been reading that one for years.

That statement looks like it could have been made by a second-year caster posting on the internet. Unqualified or subsstandiated with test data, or at least a reference to test data. Lee's book is rife with the same kind of statements, as is the whole Lyman series of publications.

I never set about proving or disproving it, it didn't seem important because I got my best groups with boolits sized, generally, a thousandth or two down from the as-cast size, because that's what it took to fit the gun or at least make it happy.

The key, I believe, is to size the boolits without bending them, bumping the nose, or shaving one side, and then fit them to the gun so that they start straight in the bore, don't "wad up" trying to get engraved due to a sloppy thoat, and get sent on their way with a powder that has a long, gentle pressure curve in that particular cartridge/boolit combo. And use a soft lube that blows off right at the muzzle so you don't have balance problems downrange.

Gear

[Char-Gar]

That statement from RCBS is self serving designed to sell their molds. It does not serve the bullet caster will, as the information is very misleading if not downright false.

In the best of world, a bullets would require no sizing, but most often we don't live in that world. In my world, bullet sizing itself does not damage bullets, but HOW they are sized does matter allot. I am talking rifle bullets here.

[williamwaco]

Been reading that one for years.

That statement looks like it could have been made by a second-year caster posting on the internet. Unqualified or subsstandiated with test data, or at least a reference to test data. Lee's book is rife with the same kind of statements, as is the whole Lyman series of publications.

I never set about proving or disproving it, it didn't seem important because I got my best groups with boolits sized, generally, a thousandth or two down from the as-cast size, because that's what it took to fit the gun or at least make it happy.

The key, I believe, is to size the boolits without bending them, bumping the nose, or shaving one side, and then fit them to the gun so that they start straight in the bore, don't "wad up" trying to get engraved due to a sloppy thoat, and get sent on their way with a powder that has a long, gentle pressure curve in that particular cartridge/boolit combo. And use a soft lube that blows off right at the muzzle so you don't have balance problems downrange.

Gear


Gear knows what he is talking about.


At the time that was written, most sizing dies were cutting dies. They had a cast size diameter lead in at the top of the die then a sharp shoulder that literally shaved away the excess lead from the side of the bullet. ( This shoulder was sharp enough to cut your finger. I know, I did it. )

With these dies, it was very easy to create oval shaped bullets.

I didn't believe those statements about sizing even back then. I know you could ruin bullets in the sizing step but I never had any accuracy problems with them. It takes only a little care and a gentle touch on the sizing handle to produce good round bullets even with the old dies.

I have not seen one of those dies in years, even scrounging through the junk at gun shows, I don't see them any more.

Todays dies are swaging dies. They do not cut, they swage and no metal is actually removed. This process decreases the diameter of the bullet by squeezing it out and it actually increases the length. For example.

Measuring the length of 16 bullets before and after sizing:

.357 Ballisti-Cast #651 drops at .360.

Before sizing, average length of 16 bullets = 0.69949
Average length after sizing of same 16 bullets = 0.70294
Sized to .357 with the Lee push through die.

I am testing accuracy with as cast and various degrees of sizing with rifle bullets now. I have completed testing handgun bullets ( to my satisfaction ) With Lyman 4500 and Lee push through sizing dies.

There is no accuracy difference between as cast bullets that drop at .361 to .362 and the same bullet sized to .359, .358, .357 or .356. I never could find a .355 die to test. I didn't really worry about .355 because I fear it will be too small to engrave properly.

Sizing from .362 to .356 is six thousandths and it has zero effect on accuracy using Thompson Contender 8x scope. S&W M19 4x scope, Win 92 with tang sight or Ruger No 1 14 x scope.

All testing was done with .357 Mag cartridge at velocities from 750 to 1650 fps.


Merry Christmas.




.

[geargnasher]

I wish I could measure boolits to five decimal places! I have a Mitutoyo that is slick enough and sensitive enough for me so measure the thickness of a fingerprint on the anvil (just under one ten-thousandth), but that's as good as I can do.

Gear

[Maven]

In the best of worlds, a bullet would require no sizing, but most often we don't live in that world. In my world, bullet sizing itself does not damage bullets, but HOW they are sized does matter allot. I am talking rifle bullets here.

Amen to that! Concentric sizing is what we want, which wasn't always possible with the old H & I sizing dies (lacked a tapered throat).

[Le Loup Solitaire]

In Col Harrison's writings, his opinion was that a good bullet comes from a good mold to start with and secondly that sizing damages the bullet. It would seem then that shooting as cast would be the ideal setup...if you are blessed. Few of us are. Most bullets need to be trued up as they are usually out of round by some measure. The keywords are in the first line...."a good mold", and that alone is something to strive for....and then it should be well cared for. A lot of good shooting was once done in the days when there were no lubrisizers....just pan lubing and cake cutters. Well whatever your arrangements or beliefs; if you are satisfied with the results and they are good then there is no need to fix what isn't broke. LLS

[1Shirt]

As a general rule, with this subject there are no general rules! Have a problem with the .001 and group dispersion at 100 if that is a general rule, cause I don't think it holds true in all cases. May not in fact be true in any case! Far to many variables that include design of blt, methods of seating, hardness of alloy, seating of GC, seating depth of blt in ctg. etc.etc.etc.
1Shirt!:coffee:

[Suo Gan]

One of the reasons for manufacturers tightening their molds is because the boolit molds of yesteryear were larger with the thought they could be sized down even dramatically without it affecting accuracy that much. This was good for the manufacturers. It is ironic that we think that the molds made years ago were made with the shooter in mind. In fact the OPPOSITE is really true. They were made to cast large to suit more guns without the need for the manufacturer or the boolit caster to buy multiple molds. The manufacturer takes a lot of heat these days mainly for producing undersize boolit molds. This is mainly due to them being willfully ignorant about the alloys casters shoot these days..mostly. It's HARD to please everyone all the time!

What RCBS is saying is sound fact. The unsized boolit is far better than the sized boolit. The boolit sized a little bit is far better than a boolit sized a lot. The reason for this is fairly intuitive.

No matter how much care, or how much you paid for your sizer and how much you think you know about the processes, you are messing a boolit up if you are sizing it to some degree. You are not making it better or more concentric, etc. by sizing a boolit (if you are you need another mold, a new casting method, some new alloy, or maybe all three). The only thing you may be doing is collapsing internal voids, and if you are getting a lot of them, you need to stop blaming molds and start blaming the one holding the mold.

This is a general idea, and it is a GOOD idea for a manufacturer to follow. They have discovered MOST guns in XXX caliber usually have XXX bore diameter. There is nothing wrong with that idea. It is just them trying to stay in business.

But most casters are frugal people. They buy one mold that drops at .312" and they size it down to .310" and shoot it in their 30-06 .309" and their 30-30 .307". If they are not target shooting they are usually happy.

But there are some of us who like to go down the list. We want the right powder, we want the right primer, etc. I will submit to you that choosing the correct boolit that fits the step and lead, a boolit that compliments your barrel twist, and barrel dimensions are just as important as any of the other and the very first thing you should be concerned with in load development and building a cartridge for Betsy.

Sizing destroys accuracy because you are putting an incredible amount of force on that little boolit over a tiny surface area. If you are nose sizing and swaging two, three, four thousandths you are putting it through a lot of stress, bending it, warping it, squishing it out of round, changing boolit geometry one from another, and if you are splitting hairs it makes a great deal of difference.

Isn't this the main reason folks buy custom molds after all so that sizing is kept to a minimum?? This is all RCBS is saying. I do not think you can disagree with them.

I really don't know about their blanket statement about degrading group size according to amount sized. I am sure that there are some instances where the opposite is true. But I believe they were speaking in generalities, and I don't think they are wrong in that regard.

Page 50 of NRA Cast Bullets has a small snippet about sizing dies etc.

For anyone that does not know it can be downloaded here for free: http://www.castpics.net/subsite2/ClassicWorks/default.html

[beagle]

Well, opinions are just like something we sit on. Everyone has one and here's mine. I prefer bullets to cast oversize by at least a couple of thou and then size down in a good concentric sizer so that you get good, well filled, complete bands.

Obviously a uniform roundness is a plus on accuracy or at least, in the case of "beagled" bullets a consistency from side to side.

I know these old sages are wise beyond my years and experience but I beleive that sizing son't hurt the OS bullets as long as it's round.

I prefer nose first sizing as I think you get less distortion of the ready to load bullet.

As far as overworking the bullet....consider a bullet fired in a revolver. First, a big boot in the butt during ignition, then the bump up when pressure comes, then the jump between the cylinder and forcing cone, then the swage down to the rifling/bore diameter and finally the exit from the barrel. Along the way, there's a little blow-by and maybe a little errosion along the sides by previous leading.

Based on this trip, what's a little distortion cause by a little exces sizing? MHO/beagle

[williamwaco]

I wish I could measure boolits to five decimal places! I have a Mitutoyo that is slick enough and sensitive enough for me so measure the thickness of a fingerprint on the anvil (just under one ten-thousandth), but that's as good as I can do.

Gear

Gear,


I can't measure them to five decimal places either. But I can average them to 16 decimal places.

That said, you and I both know that anything past the fourth "significant" digit is meaningless.





.

[pdawg_shooter]

I size the 311284 down to .3015, patch it back up to .310 and shot MOA groups. So if I didnt size it I could shoot 1 holers?

[W.R.Buchanan]

RCBS: originally set up their mould dimensions around the shrink rate of Lino type. across the board! Lino type is only appropriate IMO for small caliber Rifle boolits like for .30 and below, nobody is using linotype material for psitol boolits or large cal rifle boolits.

I actually got them to make me a new .45-300FNGC mould based on WW material. IE .002 larger than stock, and the Lino test boolits they sent me were .463-4! my WW material boolits from that mould are .461-2 which is exactly what I am looking for. I want to end up with .460 for my rifle, and they shoot well. The boolits from the original mould did not! and that one is going to Erik next year to get opened up .002, and reconstituted as a PB mould in the process.

My own personal opinion is that it is better to have to size a boolit down than to end up with one that is undersized and not round. Sizing .002 on a .45 cal rifle boolit is not moving it very much percentage wise. This is why I want all of my moulds large, that,,, and I have never gotten good accuracy from a small boolit.

Shooting a boolit that is .001-2 larger than the bore will be taken care of by the bore and the pressure. Shooting one that is undersized can only create problems,,, UNless it is a hollow base boolit.

We have talked about this several times before and it all comes down to personal preferrence because I don't think anybody has all the answers on this subject. It all comes down to what your opinion is on the subject, based on your personal experience.

Gear: You need one of these. It reads to 10 Millionths. I can extrapolate my Lee hardeness tester impressions to .1 BNH easily!

Randy

[fredj338]

I would say the opp is true. A bullet of uniform size fits the brass the same in each case. So more uniformity across the board should mean more uniuform vel & bullet release w/ greater accuracy from shot to shot.

[MtGun44]

+1 on Gear and William, esp the old style cutting shoulder type of sizer. I think there
may have been some truth in those days, but I think that is long gone and if you do it
carefully like Gear says, I think this moves out into either an old wive's tale or just
such a small effect that it would take a heck of a lot to prove it and even if you did,
who knows if it would apply across the board?

It is not a bad thing to have you boolits drop at the right diameter, but most problems
are too small by a large margin, so if RCBS is running scared of this particular boogy man,
they are doing us all a disservice by making their molds too small.

I guarantee you that people have 25 SERIOUS problems for too small for every real
problem from too large.

Bill

[geargnasher]

I size the 311284 down to .3015, patch it back up to .310 and shot MOA groups. So if I didnt size it I could shoot 1 holers?

Thanks, Pdawg, I was about to mention that after reading Suo Gan's post. Knocking .010" or more off of a boolit, sometimes all at once, doesn't seem to hurt my patched boolits one bit. Seems I'm not the only one shooting tiny groups at obscene velocities from standard sporter rifles using drastically manipulated boolits. The sizing ain't done once the boolit is loaded, either. It gets a good squeeze in the bore too when the patch engraves. It's all about how you do it. The only time severe sizing has been an issue for me is when I tried to reduce the boolit's size by wrapping oversized and THEN swaging patch and boolit together. Never could get uniform boolit diameter that way.

Gear

[geargnasher]

Randy, that's one neat device! If only the spring in the Lee tester was as accurate. It's close to 60 lbs, real close on mine, but not exact.

Gear

[mroliver77]

buckshot did a write up on this some years ago. He shoots some calibers that moulds are not readily available for and had sized some rifle boolits down like .010" or .015". His results did not confirm the RCBS statement.

I try to fit boolits to the chamber/throat. Some of our older guns especially in the transition from bp to smokeless era have grossly oversize neck-throat set ups. Some mil surp guns have sloppy throats and can benefit from boolits much larger than groove diameter. It is hard to stock custom mould for every rifle so an oversize boolit can be handily sized DOWN to fit many different guns. Some of us even size the bore riding section for certain guns.

It is accepted "fact" that micro groove barreled guns need hard boolits because of the shallow rifling. I do not agree. The Marlin MG barrels don't have a lead/throat/seat like most guns. It is a kind of short funnel from the OD of the neck size to the bore size. This is hard on cast boolits but harder boolits get beat up less.

I routinely size boolits down .001"- .004" and get 2" or better groups depending. Boolits that drop and need no sizing can shoot the same, better or worse.

In a nutshell I cast slightly out of round boolits. Size them in a slightly out of round die. Then fire them in a gun with a slightly (or grossly) out of spec chamber and usually a warped barrel.(Stick any factory barrel between centers in a lathe and put an indicator on it.) The boolit is mashed in the butt by extremely high pressure gas then squished into a thin tube cut with threads that force it to spin 20,000 rpm and accelerate to 900mph in a fraction of a second. I am am amazed that it works at all much less ring steel at hundreds of yards.

[BOOM BOOM]

HI,
MOLDS that drop perfectly round bullets, not that common.
SIZERS that are perfectly round, not that common.
BARRELS that have perfect throughts, leads, perfectly round bores, that are perfectly concentric, not that common.
We try for this, but live in an imperfect world.

Then there is the brass, and those imperfections.
Then all the possible mistakes/ imperfections in the loading process.

Then the differences in the shooting process.

There are some who can shoot 1 hole groups. ITS AMAZING.

You just have to experiment & find out what fits your gun and your reloading process.:Fire::Fire:

[cajun shooter]

RCBS moulds were at one time much better than those offered today. I have used nothing but custom moulds for the past 5 or 6 years. I then have Lathesmith make my Star dies which are works of art. He does have the ability to make them so concentric that after sizing a bullet you can see where it was sized its entire circumference.
When I had a RCBS lube/sizer the bullets would have high and low spots when using factory dies. That's sad for a machine that makes two passes through the die.
I had to laugh the other day while reading a posting by a new member. He was in a peeing match with another member and the statement he made was funny as all get out. When he was questioned about the source of his expertise his answer was that he had read all of Richard Lee's book cover to cover. Later David

[Bret4207]

IF we could reduce the variables between boolits and brass then we'd have more accurate loads across the board, simple as that. RCBS made what is essentially a true statements if you work within a certain set of parameters ie- garbage in, garbage out. OTH, if you have decent boolits to start with, decent sizer dies, are aware of your sizers limitations and quirks and are ruthless in your quality control then your sized boolit may shoot better than another group that is unsized.

Too many variables to make blanket statements IMO. It's just more evidence that fit is King in this game.

[Bret4207]

RCBS moulds were at one time much better than those offered today. I have used nothing but custom moulds for the past 5 or 6 years. I then have Lathesmith make my Star dies which are works of art. He does have the ability to make them so concentric that after sizing a bullet you can see where it was sized its entire circumference.
When I had a RCBS lube/sizer the bullets would have high and low spots when using factory dies. That's sad for a machine that makes two passes through the die.
I had to laugh the other day while reading a posting by a new member. He was in a peeing match with another member and the statement he made was funny as all get out. When he was questioned about the source of his expertise his answer was that he had read all of Richard Lee's book cover to cover. Later David

I read pretty mcuh everything Louis L'Amour wrote. Must be I'm a cowboy!:drinks:

[Char-Gar]

IF we could reduce the variables between boolits and brass then we'd have more accurate loads across the board, simple as that. RCBS made what is essentially a true statements if you work within a certain set of parameters ie- garbage in, garbage out. OTH, if you have decent boolits to start with, decent sizer dies, are aware of your sizers limitations and quirks and are ruthless in your quality control then your sized boolit may shoot better than another group that is unsized.

Too many variables to make blanket statements IMO. It's just more evidence that fit is King in this game.

Amen and Amen!

[cbrick]

RCBS moulds were at one time much better than those offered today. Later David

This has not been my experience, not even close. RCBS did have some problems a few years ago but solved them with new CNC machines and my newer RCBS molds are some of the best, easiest casting of the 70+ molds I have.

As for sizing hurting accuracy I agree with the statements that there are simply far too many variables involved to make a blanket statement of yes or no. I am pretty well convinced though that nose first sizing in a push through sizer does result in a more concentric bullet. Proved this to myself several years ago with a machine shop comparator with bullets from the same mold sized in a Star, RCBS and SAECO lubrisizer. It would take an awful lot to convince me that a more concentric bullet isn't a more accurate bullet.

Rick

[williamwaco]

This is a good thread, since nobody has done so - I am giving it 5*
There is lots of really good information here - Not all of it but most of it.

I am going to add one more opinion then retire.

-------------------------------------------------------------------------------------------------------------------

I would love to have a copy of Col Harrison's book. I remember reading his stuff many years ago - when I was a kid.

He was a giant of the industry.

I can tell you this though. His research was done in the days of the "shaver" sizing dies. There is no comparison with the modern sizing dies and his results do not apply to the swage dies we use today. Further, the most accurate handgun bullets in the world, factory wadcutters, are created by swaging pure lead in a process almost identical to the process used by modern sizer-lubricator machines.

I can tell you one more thing. All bullets are "sized". Even jacketed bullets are "sized". The ultimate sizing die is the barrel and all bullets are sized by that die.

Only the very best custom molds drop bullets that are "round" within less than one thousandths of an inch. I have exactly two molds that cast "round" bullets. They are "round" +/- .0005.

Every one of my mass market molds drop bullets that are out of round by anywhere from .001 to .003. To compound the issue, the same cavity of the same mold from the same pot of metal on successive fillings will drop bullets of different diameters by .0005 to .001.

When I first read about the Lee method, I didn't believe a word of it. EVERYONE knows that will not work. In experimenting with the Lee method, I found it does work. I can find no difference in the accuracy of bullets fired "as cast" and the same bullets sized by as much as .006.

All these bullets produce sub 1" at 50 yards with handguns ( scoped ) and and sub one inch at 100 yards with rifles ( with an occasional sub one half inch )

This means that a bullet that is out of round by as much as .003 is not necessarily going to be inaccurate. Is this due to the swaging of the bullet by the bore? I don't know.

I do know that the bullet exiting the bore is almost perfectly round regardless of how round it was when it left the cartridge case.


I also a know couple or other things:

Things that are "intuitively obvious" are very frequently wrong.

Things that "Everyone knows to be true" almost never are.

[geargnasher]

WW, some kind and patient soul scanned that book and made it available to us all. Go to Castpics dot net and look in the classic articles section (IIRC). Somewhere on the site is a list of downloadable PDFs of different classic books, Col. Harrison's being one of them. Download it and either save it to a file or print it out and put it in a three-ring binder, it's worth the paper and ink cartridges to do so.

One more thing, a boolit that's fully engraved will be as round as the barrel will allow at the driving bands regardless of previous processes, but the nose might not be concentric with the bands and the base might not be square, and the bottom of the lube grooves might not be concentric with the bands either, creating embalance in flight. A bent nose has aerodynamic issues, and an unsquare or damaged base will tip the boolit on muzzle exit. We have to work through the whole loading and firing process to minimize these detrimental effects.

Gear

[williamwaco]

WW, some kind and patient soul scanned that book and made it available to us all. Go to Castpics dot net and look in the classic articles section (IIRC). Somewhere on the site is a list of downloadable PDFs of different classic books, Col. Harrison's being one of them. Download it and either save it to a file or print it out and put it in a three-ring binder, it's worth the paper and ink cartridges to do so.

One more thing, a boolit that's fully engraved will be as round as the barrel will allow at the driving bands regardless of previous processes, but the nose might not be concentric with the bands and the base might not be square, and the bottom of the lube grooves might not be concentric with the bands either, creating embalance in flight. A bent nose has aerodynamic issues, and an unsquare or damaged base will tip the boolit on muzzle exit. We have to work through the whole loading and firing process to minimize these detrimental effects.

Gear



Thanks for that heads-up about that book. I appreciate it.

Exactly, I agree, you are correct on every point.

The thread was about sizing so that is all I was commenting on.

By the way.

I am not a gunsmith, machinist, and claim no expertise in anything of that sort. With that caveat, it seems to me that I have learned from slugging bores that they are slightly more "round" than sizing dies. would you agree or not?



.

[geargnasher]

I am not a gunsmith, machinist, and claim no expertise in anything of that sort. With that caveat, it seems to me that I have learned from slugging bores that they are slightly more "round" than sizing dies. would you agree or not?

Me neither!

The thing that keeps tripping me up on this whole "sizing quantity vs. accuracy" thing is that the static, or initial, fit of a boolit in a gun is only partly responsible for the final accuracy potential of the "weapon system". I've slugged enough bores all the way through, into both ends a few inches and out, halfway through and back out, etc. to determine that many production barrels have some inconsistencies in them that are greater than those of the average boolit I load. Mostly the barrel issues are due to roll-lettering, front sight placement, etc. How much it matters depends a lot on boolit size. A groove-diameter boolit is going to be much more sensitive to dimensional dynamics during it's trip down the bore than a boolit that's a bit larger and under compression.

I haven't done a lot of actual measuring of sizing dies, I measure what they produce, and some are better than others. A boolit that begins elleptical will still be elliptical after sizing due to springback, unless it's made from a really soft alloy. Regardless, the barrel will make of the boolit what it will, so I try to get fairly close but don't lose much sleep if the boolits are still a half-thousandth out of round when I load them.

The only other thing I can think of that would make RCBS conclude what they have is the "work softening" effect of excessive sizing on the bands. But that's an entirely different discussion!

Gear

[drklynoon]

I didn't buy RCBS statement but I am sure glad I read this whole thread. Thanks guys you are a wealth of knowledge. Oh and a BIG thank you to whomever downloaded the books. I now have all of them downloaded and will start the printing presses this weekend. :-)

[Bret4207]

Me neither!

The thing that keeps tripping me up on this whole "sizing quantity vs. accuracy" thing is that the static, or initial, fit of a boolit in a gun is only partly responsible for the final accuracy potential of the "weapon system". I've slugged enough bores all the way through, into both ends a few inches and out, halfway through and back out, etc. to determine that many production barrels have some inconsistencies in them that are greater than those of the average boolit I load. Mostly the barrel issues are due to roll-lettering, front sight placement, etc. How much it matters depends a lot on boolit size. A groove-diameter boolit is going to be much more sensitive to dimensional dynamics during it's trip down the bore than a boolit that's a bit larger and under compression.

I haven't done a lot of actual measuring of sizing dies, I measure what they produce, and some are better than others. A boolit that begins elleptical will still be elliptical after sizing due to springback, unless it's made from a really soft alloy. Regardless, the barrel will make of the boolit what it will, so I try to get fairly close but don't lose much sleep if the boolits are still a half-thousandth out of round when I load them.

The only other thing I can think of that would make RCBS conclude what they have is the "work softening" effect of excessive sizing on the bands. But that's an entirely different discussion!

Gear

Once again Gear beat me to it. Add to all the variables we find with moulds, dies, sizers, etc. the variations in brass, throats, rifling, bore, muzzle, etc. If we were really going at this for the absolute best we could get we'd be doing the benchrest thing with turned necks, weighed and sorted brass, custom cut chambers and barrels, multiple QC checks on runout, seating depth, nose deformation, etc., etc. The crazy part is that sometimes, too often in fact, the variables seem to stack up in our FAVOR through some weird chance and pick up loads with unsorted boolits will plop 10 inside an inch or something. We could try for a lifetime to duplicate that series of variables and never do it!

[williamwaco]

Once again Gear beat me to it. Add to all the variables we find with moulds, dies, sizers, etc. the variations in brass, throats, rifling, bore, muzzle, etc. If we were really going at this for the absolute best we could get we'd be doing the benchrest thing with turned necks, weighed and sorted brass, custom cut chambers and barrels, multiple QC checks on runout, seating depth, nose deformation, etc., etc. The crazy part is that sometimes, too often in fact, the variables seem to stack up in our FAVOR through some weird chance and pick up loads with unsorted boolits will plop 10 inside an inch or something. We could try for a lifetime to duplicate that series of variables and never do it!


Yeah, I have done that too. ( minus the custom barrel ). With a very accurate 1885 highwall. Didn't make one whit of difference.

I have read a lot about the extreem accuracy tips. I have tried all of them I could afford. None of them made any difference at all.

Now I will opine on something I don't know anything about. My opinion is that if you paid less than $4,000 for your custom bench rest rifle. Forget it.

If you can shoot quarter MOA every time without these tips, they might get you down to one fifth MOA. If you are not already at or below one half MOA, you are wasting your time.

I have owned many production sporter grade rifles that would shoot three fourths to one half MOA reliably with NONE of the extreem accuracy "tips". That means unsorted, unweighed, untrimmed, unneck turned, uncleaned primer pockets brass, loaded with thrown charges and with plain old production dies. In those days the seating dies did not even have the sliding sleeve to hold the bullet concentric with the case neck.

Of course I have also owned many similar rifles that would not shoot 2 MOA with the exact same ammo.

In many cases, a truly accurate, tack driving, production grade rifle is more of an accident than the result of anything we did. When you get one, never let it go.



Again,

Merry christmas

[MtGun44]

One side note on Harrison's work. WAY back when I was a teen and decades before I
cast anything except 350 gr SWC Minie bullets for a friend's original 1863 Springfield
rifled musket, I got the NRA Illustrated Reloading Handloading book. This is basically
a compendium of Am Rifleman articles originally published in 1959, and I bought it about
6 yrs later. The Harrison articles were in the book and I read them avidly.

In re-reading them a few years ago, I noted that Harrison tended to use boolits that were
right at groove diameter in all his loads. I was surprised at this because Lyman recommended
.310 for .308 nominal barrels and I have had good luck with .310 and .311 diameters, never
actually tried .308 or .309 diameters. I use wwt alloy, air cooled and maybe with hard alloy
or heat treated there may be differences. I have not even come close to exploring all of the
variables out there, and will not live long enough, even if I tried. I'll have to take the advise
of some that have tried some stuff and see which of the "most likely" recommendations do
work for me.

Bill

[cbrick]

I've slugged enough bores all the way through, into both ends a few inches and out, halfway through and back out, etc. to determine that many production barrels have some inconsistencies in them that are greater than those of the average boolit I load. Gear

I slug all of my bores also but what really opened up my eyes was the bore scope. The only way to know for sure what the bore looks like is to use a magnifying scope and look at the entire bore up close and personal. If you don’t really want to know you shouldn’t look, talk about inconsistencies. A good look at your favorite bore could keep you awake at night. Amazing some of them shoot at all.

Rick

[geargnasher]

Good point Rick, I've put off buying a bore scope just for that reason! I don't really want to know. If they shoot straight, that's good enough for me.

Gear

[Recluse]

I remember reading how the wise old minions also decreed at one point that the world was flat, and they offered up all kinds of anecdotal evidence and theories as to why.

Actual exploration proved otherwise.

That's how I approach casting and handloading.

:coffee:

[williamwaco]

Good point Rick, I've put off buying a bore scope just for that reason! I don't really want to know. If they shoot straight, that's good enough for me.

Gear



I agree with that completely.

This is probably going to get me in trouble here but in my entire life I don't think I slugged but one bore and that was strictly to see if I could do it.

Now I have slugged almost everything I own since I joined this forum. You know what I learned from that exercise?

1) 9mm bores are not .355 like the experts have been telling me since God was a teenager.

2) Three different brands of 9mm Jacketed ammo I miked came in at .354 and both my 1911 9mms slugged .357. No wonder people complain about the accuracy of the 9mm. It is a wonder those slugs manage to hit the target point forward.

3) What else? Nothing. Every other firearm I own slugged exactly what SAAMI says it should.


Gear, save your money. If a gun doesn't shoot and you ( of all people ) can't make it shoot, trade it off. Get one that will shoot.

You can buy some seriously nice guns for the price of a bore scope.


Merry Christmas.




.

[cbrick]

I agree with that completely. Merry Christmas.

Completely misses the point of how much you can learn from using a bore scope. That alone is worth the cost to me.

As an example, think your bore is clean? Would you like to make a little wager on that?

Rick

[ghh3rd]

And use a soft lube that blows off right at the muzzle so you don't have balance problems downrange.

Gear -

I've heard that some boolits that have been pulled from a berm still had chunks of hard lube in the grooves. Must be tough lube to survive the spin, but if chunks remain, it seems the accuracy would suffer. I like Felix lube since I make it soft, and think it must spin right off the boolit evenly as it exits the barrel.

Randy

[williamwaco]

Completely misses the point of how much you can learn from using a bore scope. That alone is worth the cost to me.

As an example, think your bore is clean? Would you like to make a little wager on that?

Rick

Rick, I actually understand your point. I just don't care. I understand that you can learn a lot and if that interests you it is a fabulous gadget to own. I don't fault you at all for buying one. I would just rather have a new gun, or a new laptop, or a new progressive press, than a new bore scope.

[geargnasher]

I gotcha, Rick, but OCD people like me have to draw the line somewhere or we'll never sleep. I agonize over small details of fit, anneal, boolit toughness, lube tweaks, and other things enough as it is. I don't do a lot of benchrest shooting, and my only real competition is myself. I've seen a few bores through good scopes before and all the cracks and erosion in the throats, not to mention fouling of all sorts and horrible tooling marks does indeed make one wonder how they shoot at all.

As a rule, I try NOT to clean my bores, but get them shooting good and leave them alone except for a quick wipe out and maybe light oiling once in a while. I quit being a fastidious bore cleaner when I quit needing to remove gilding metal fouling, seems that since I put all of that behind me and switched to cast or paper-jacketed exclusively most of my guns shoot better with "seasoned" bores than squeaky-clean ones.

A bore scope will certainly end an argument about "zero leading" statements quickly, but if there is in effect zero leading, meaning that accumulations are small, stable, and don't grow or move around shot after shot and the gun is accurate, then it might as well actually be zero. When I say "zero", I mean that I can clean the bore and not find any with a bore light or on the patches, nor can feel any with a tight, dry patch.

Just my take on it, but I have different needs and objectives than a lot of shooters do, and can tell pretty quickly if a gun can be made to shoot or not without a microscope to tell me exactly why.

Gear

[geargnasher]

Gear -

I've heard that some boolits that have been pulled from a berm still had chunks of hard lube in the grooves. Must be tough lube to survive the spin, but if chunks remain, it seems the accuracy would suffer. I like Felix lube since I make it soft, and think it must spin right off the boolit evenly as it exits the barrel.

Randy

The experience that removed all doubt for me was a set of 100-yard targets from my "good" .30-'06 when I was first tinkering with Felix lube a couple of years ago. The first batch I made didn't impress me at all, in fact gave me worse accuracy than my long-proven favorite load using Lyman Alox. When I saw the target in person there were little flecks of lube stuck to the paper of the Felix lube targets, but not to the Alox targets fired immediately before. I went and shot another group of Alox-lubed boolits, same load, and the expected accuracy returned, and the lube flecks disappeared. So I went home and cooked some more oils up and added them to the lube with a touch more soap but did not increase the lanolin content (at this point I was adding no carnauba wax). The lube was much softer, and the next range session showed an even better than average group size, and better still, a very round, predictable dispersion. I loaded a bunch more and tried them on several different occasions, and the more I shot the boolits lubed with Felix lube, the better things got. Then came winter time. Guess what? The flecks returned and the accuracy went to pot. So I tweaked it again, and my accuracy returned. Then I shot some of those same loads on a hot day in the spring and got fliers every three or four shots. That's when I learned about lube purging, and went back to formula #2, which got me back to my best groups again. Then I made the mistake of cleaning the bore really well, and it took a couple of range sessions and me almost tweaking the lube again until it started shooting well again. Is any of this conclusive? No, except for maybe this one gun, but the trend has seemed to more or less be the samewith my other rifles: Use a lube with the lubricity and viscocity suited to the climate, pressure, and velocity, and let the barrel season. If the lube doesn't jettison at teh muzzle, it's going to adversely affect accuracy (I assume) because it upsets the boolit's balance multiple times on the way to the target each time a piece flings off. So now, once a gun starts shooting straight, I don't screw with it too much. Perhaps these experiences have boxed my thoughts into a corner, but I can only go from my own experiences and so far it's working well for me.

Runfiverun put it quite well with regard to lube, he said it either needs to "all stay or go", anything in between will cause problems.

Gear

[Tatume]

I wish I could measure boolits to five decimal places! I have a Mitutoyo that is slick enough and sensitive enough for me so measure the thickness of a fingerprint on the anvil (just under one ten-thousandth), but that's as good as I can do.

Gear

It is proper to round statistics to one decimal place more than the original data. If the data were mearured to four decimal places, then five would be correct for the average. This does not imply that the average can be replicated with the measuring instrument.

Take care, Tom

[Tatume]

As a rule, I try NOT to clean my bores, but get them shooting good and leave them alone except for a quick wipe out and maybe light oiling once in a while. I quit being a fastidious bore cleaner when I quit needing to remove gilding metal fouling, seems that since I put all of that behind me and switched to cast or paper-jacketed exclusively most of my guns shoot better with "seasoned" bores than squeaky-clean ones.
Gear

+1 Yesterday I pushed a tight patch though one of my Winchester High Wall rifles, just to see what I would find. There was a bit of black on the patch, and it was slightly greasy with lube. Perfect!

Chambers, on the other hand, sometimes have to be cleaned. When my cases start showing excessive lube on them, I use a pistol cleaning rod to clean the chamber. It takes about two minutes with a tight patch and WD40.

Take care, Tom

[cbrick]

As a rule, I try NOT to clean my bores, but get them shooting good and leave them alone except for a quick wipe out and maybe light oiling once in a while. I quit being a fastidious bore cleaner when I quit needing to remove gilding metal fouling, seems that since I put all of that behind me and switched to cast or paper-jacketed exclusively most of my guns shoot better with "seasoned" bores than squeaky-clean ones. Gear

I'll clean my match revolver bore about once a year, I get very little lead out of it but lube and powder fouling does seem to dry and build up after several hundred rounds fired and in time accuracy starts to go south, talking 700-800 rounds. After cleaning it at least 50 rounds must be fired to "season" the bore to return both groups and sight settings for the 50-100-150-200 meter distances.

The cylinder is another matter, that gets cleaned after every shooting session. Lube will build up in the chambers to where both chambering and extraction gets sticky after just 3 or 4 shooting sessions.

Lube sticking to the bullets I think has much to do with the lube of course but also what cartridge and the pressure/velocity it's fired at. Using the same lube in the 45 ACP 1911 fired at 800 fps recovered bullets lube grooves are still full. The same lube fired from high end 357 mag loads and recovered bullets show no trace of lube.

Rick

[geargnasher]

It is proper to round statistics to one decimal place more than the original data. If the data were mearured to four decimal places, then five would be correct for the average. This does not imply that the average can be replicated with the measuring instrument.

Take care, Tom

I don't follow, but I get lost easily, too! From what I'm used to, how many "significant" digits one uses for the final answer depends on the least precise piece of data used, but that's for different math. Statistics has its own rules as I remember. :killingpc

Gear

[pdawg_shooter]

Me neither!

The thing that keeps tripping me up on this whole "sizing quantity vs. accuracy" thing is that the static, or initial, fit of a boolit in a gun is only partly responsible for the final accuracy potential of the "weapon system". I've slugged enough bores all the way through, into both ends a few inches and out, halfway through and back out, etc. to determine that many production barrels have some inconsistencies in them that are greater than those of the average boolit I load. Mostly the barrel issues are due to roll-lettering, front sight placement, etc. How much it matters depends a lot on boolit size. A groove-diameter boolit is going to be much more sensitive to dimensional dynamics during it's trip down the bore than a boolit that's a bit larger and under compression.

I haven't done a lot of actual measuring of sizing dies, I measure what they produce, and some are better than others. A boolit that begins elleptical will still be elliptical after sizing due to springback, unless it's made from a really soft alloy. Regardless, the barrel will make of the boolit what it will, so I try to get fairly close but don't lose much sleep if the boolits are still a half-thousandth out of round when I load them.

The only other thing I can think of that would make RCBS conclude what they have is the "work softening" effect of excessive sizing on the bands. But that's an entirely different discussion!

Gear

A fellow I know bought 6, yes 6 of the same size sizing die trying to find one that gave a perfectly round bullet. I ask him to please explain to me how any bullet can travel down 16 to 24" of round barrel with 30 to 60 THOUSAND psi behind it and exit in any shape BUT round? He has since quit wasting money searching for perfection.