How do you FIT a boolit or design it for a lever action with a deep throat?

[MBTcustom]

I was recently the honored recipient of a Rossi 92 carbine in 44Mag.
I set about to design a boolit for this rifle and found that perfect fit is impossible.
The throat starts at the case mouth @ .459 and tapers straight to the groove diameter at an angle of 3 degrees, 47 Minutes of angle per side.
What this means is that about .200 from the case mouth to the groove diameter is unsupported in the chamber. Ie, if I had a perfectly flat nosed wadcutter, it would have to stick out of the case .200 just so that the leading edge could touch the rifling.

OK, so I designed a boolit that was .432 in diameter till it touched the rifling .200 from the case mouth, then has a 4 degree 47 minute angle to bore diameter, then about .020 bore rider, then a nice short TC nose about .125 long.
What this equated to was a boolit that protrudes from the brass by .450 with an OAL of 1.720 and I turned said boolit out of tool steel to check fit and function in the rifle.

When single fed into the rifle, this boolit fit's like a glove. Perfecto.
However, it's too blessed long to feed from the magazine tube. Sure looks to me like this rifle will only eat ammo that is 1.575 long and that's probably pushing it.
The problem is that this demands that I jump the boolit to the rifling by about .150 inches. That's one heck of a jump.

So my question is twofold:
1. How is this designed around?
2. How is accuracy achieved jumping a boolit over 1/8" into the rifling?

Any advice is appreciated. Please understand that I am a bolt action guy, and that is probably horribly obvious to those of you who are reading this, so please feel free to line me out.
Thank you!

[DeanWinchester]

Would this work?

Wonder if it'd feed reliably.


http://www.accuratemolds.com/bullet_detail.php?bullet=43-270H-D.png

[C. Latch]

Doesn't sound any worse than shooting .38s in a .357........

[MBTcustom]

Would this work?

Wonder if it'd feed reliably.


http://www.accuratemolds.com/bullet_detail.php?bullet=43-270H-D.png

It would if the .430 diameter went all the way to the radiused edge!

[MBTcustom]

Doesn't sound any worse than shooting .38s in a .357........

Yeah, unless of course you are doing like I do and shooting 200grain RN boolits in it.

I'm OK with jumping, I just wonder how you design a boolit to jump like that?
Give it wings like a flying squirrel?
LOL!

[BCRider]

Consider that even with the 0.2" jump that it's still FAR less then the jump the bullet makes in a revolver.

Also if your theoretical wad cutter would need to stick out 0.2" then for most bullet shapes that are properly "heavy" for use in a rifle the riding skirts will have engaged at or a little before the point that the heel of the bullet has left the casing mouth. That seems like pretty good support to me. Granted it's not an "engrave upon chambering" like seen in some target rifles. But we're talking about a lever rifle, not a single shot bolt action where the shooter would be willing to live with some tightness in the chambering. So the chamber has to have a little more room in it to allow for round nose bullets.

Speaking of which I just went and checked. The Lee 429-240-2R mold I've got for a full round nose cast with the base of the nose ogive at the same size as the skirt would engage the rifling that much sooner than a SWC shape or a Kieth style.

[MBTcustom]

Consider that even with the 0.2" jump that it's still FAR less then the jump the bullet makes in a revolver.

Also if your theoretical wad cutter would need to stick out 0.2" then for most bullet shapes that are properly "heavy" for use in a rifle the riding skirts will have engaged at or a little before the point that the heel of the bullet has left the casing mouth. That seems like pretty good support to me. Granted it's not an "engrave upon chambering" like seen in some target rifles. But we're talking about a lever rifle, not a single shot bolt action where the shooter would be willing to live with some tightness in the chambering. So the chamber has to have a little more room in it to allow for round nose bullets.

Speaking of which I just went and checked. The Lee 429-240-2R mold I've got for a full round nose cast with the base of the nose ogive at the same size as the skirt would engage the rifling that much sooner than a SWC shape or a Kieth style.

OK, so that design looks like it engraves with a much more acute angle. Is this a design requirement for best accuracy?
Also, that boolit looks like it has only about 50% bearing surface which I would consider "no es bueno" in a bolt gun.
very strange.

[Pb2au]

In reference to your 1.720" OAL target.....
There is a little lee way in the carrier stop you can play with ( please read attack with hacksaw, dull files and a 8" snag grinder to create more room for a longer OAL), but I am not too sure there is 0.145" worth of it. It might be worth some exploratory surgery, but again, I don't remember how much meat is there to play with.
The other challenge after that would be ensuring that the cartridge would transition correctly into the chamber. Rossi was nice enough to bevel the chamber mouth for straight wall cartridges, and there is a little room there for massaging, but not a lot.

[MBTcustom]

In reference to your 1.720" OAL target.....
There is a little lee way in the carrier stop you can play with ( please read attack with hacksaw, dull files and a 8" snag grinder to create more room for a longer OAL), but I am not too sure there is 0.145" worth of it. It might be worth some exploratory surgery, but again, I don't remember how much meat is there to play with.
The other challenge after that would be ensuring that the cartridge would transition correctly into the chamber. Rossi was nice enough to bevel the chamber mouth for straight wall cartridges, and there is a little room there for massaging, but not a lot.

"Attack with dull files and an angle grinder" LOL! Thats funny.
I am very aware of what I can do to improve the problem with my 3700lb magic wands, but im thinking about bullet design only. Bullet design. Not gunsmithing.
Are these rifles accurate? How?
Im going to be shooting this one with an old Ideal RN design and ill see how it works.this rifle is not a target rifle, and I understand that, but I wonder what is the best boolit design for a rifle witb a long throat. What works best when you have to jump?

[Pb2au]

I have one in 45colt, and so far I am hovering around 3 inches at 75 yards. This is with the Lee 255 RNFP boolit kicked with a modest amount of 2400.
The chamber/throat relationship is a bit generous let's say. I hear and understand your agro about the long jump to get the boolit into the rifling.
At least with mine, it seems the rifling is a bit shallow to boot, so the fit (as always) is muy important.
To my shame, I haven't measure the twist rate on mine, but it definitely likes heavier boolits. In a test, I tried Lee's 300 grain RF boolit and the groups fell right into 1.25" at 50 yards. But other than maybe hunting dinosaurs, that boolit is for destroying watermelons here in Ohio.
Another thing to check is the fit of the forearm. Those wacky Brazilians don't waste a lot of time on the fit and finish of the woodwork, and pinching along the forearm is common and can impact your performance.
While you have the forearm off, you will notice the screw that secures the barrel band intercedes a bit to the radi of the barrel. That is a nice way of saying they probably filed a notch in the underside of the barrel to help pass it through. The short story is that is can and will argue with you getting the crazy thing lined back up.
The fix I came up with for a friends rifle was to relieve the center section of the screw and essentially reduce the diameter in the center of the screw. In machine building we called them French screws. (I have no idea why, and the old fellow I apprenticed with never bothered to tell me. He was too busy yelling at me on what a rotten job I was doing scraping in machine ways.....)
Anyway,,,,,
Actually my next plan of attack for this rifle is to
1)utilize 3 F black powder and a softer alloy as a test.
2)and or up my size of boolit, as I think .452" is still leaving too much slop in the throat. Again,,,generous dimensions,,,,,

It sounds like an interesting project Goodsteel, and I plan on staying tuned in here!

[btroj]

Stop thinking of fit as a static thing. Fit changes as the bullet moves, doesn't it? Make a bullet that self centers some in the throat and it will shoot plenty good for that rifle.


http://i1348.photobucket.com/albums/p733/Btroj/image_zpsf1334105.jpg (http://s1348.photobucket.com/user/Btroj/media/image_zpsf1334105.jpg.html)

Look at that bullet, it is the best shooting bullet in my 45 Colt Marlin. No idea how well it fills the throat, don't care. The nose tapers smoothly into the body so it can find center as long as I get it close.

Fit isn't as simple as making a bullet fill the throat and touch the lands. It is far more than that. It also changes as the bullet moves and obturates. Think about that and the rest is pretty easy.

[GoodOlBoy]

i agree with Btroj as well.

I would also like to throw out that my rossi 45LC old model 92 carbine has no bullet design that can even remotely touch the rifling, and on top of that it has never needed it. a 250-255 grain RNFP BB or PB bullet will shoot 3/4" at 75 yards with iron sights while standing IF I do my part. The only modification I ever made to get it from a 3" group down to that was to replace the rear sight with a marbles semi buckhorn sight. MUCH better sight picture, MUCH faster on target, and MUCH more accurate for ME than that piece of tin that was on it when I got it.

GoodOlBoy

[Tar Heel]

Well....just speculating here....a Rossi lever action for one is not really a precision machined National Bureau of Standards rifle.
As with your bolt action, a little freebore can be a good thing to give the bullet some run-up space. Are you perhaps attempting to get precision and perfection from a rifle designed for "average" work and accuracy? Nothing wrong with that except you may need to change your name to Don Quixote de la Mancha.

[brotherdarrell]

I have a Puma in 45 colt. It shoots the Lee 255 rnfp slightly better than the rcbs 270 saa, which is around an inch at 50 yds. I dont know what the throat looks like and I have never tried to find out. In fact it is the only rifle I have I have never done an impact slug of the throat and I dont imagine I ever will. I would also add that the fired cases have a bulge that would do a glock proud. This is a case of accepting what I have and not questioning it, which is out of character for me.

Darrell

[Motor]

I don't know your difinition of accurate. Are we talking bench rest or what?

There are plenty of very good shooting rifles out there that have a LOT of bullet jump. Ask anyone shooting milsurps like Mosin Nagants. If I loaded my M39 Fin to touch the rifling there wouldn't be any bullet in the case. Yet it will shoot 1" groups with my hand loads.

I think you are over thinking this. Just buy or cast some "normal" boolits and see how it does first.

I'm pretty sure we shot cast 44 special from a Puma 92 44 mag. How much boolit jump is that ! :)

[MBTcustom]

I really apreciate the discussion fellers. Good info.
What is my accuracy standard? Doesn't matter in this case. I want the best I can get from any rifle, and I have always approached that by making an informed scientific decision. Ihave devoted many hours to the study of boolit design as it pertains to bolt guns. My philosophy is:
Match the angles.
.001-.002 oversize
Do not size any more than I have to
Make the GC .001 bigger than the body diameter
Jump .001-.020 to the lands
Use the softest boolit I can get away with.

This lever gun has shot all of that to pieces. It's funny actually. Here I am looking at this rifle and I don't get to use any of my normal tricks LOL!
Heck even the Marlins let my feel the boolit when I close the action! With this gun, the cartridge will be laying in the chamber like a ping pong ball in a piece of PVC pipe. Just hanging there in space. That aint a throat, it's a corral!

Just a different scenario than I am used to.


So, with this gun you just jump to the lands. OK cool. Got it.
How do you decide what sort of nose to put on this baby? I know you want a nice taper so that it guides itself, but what's the ideal scenario? Do you match the lead angle? More acute? More obtuse?
What's you guys opinion on that?

[rpludwig]

suggest you pm forum member NSB on this topic, or perhaps he will chime in...

[MBTcustom]

Thanks, I'll do that!

Hmmmm, we have no member named NSB. Would that be HNSB?
Please advise.
Thank you.

[Nobade]

Tim, take a look at the Ranch Dog 175 designed for the Marlin 357 carbine. Essentially a wadcutter with a very short nose on it. Gets the full diameter part as close to the throat as possible and still allows feeding. So far it's the only 357 boolit I have gotten to shoot very well in rifles using smokeless powder and not paper patched. Something like that scaled up is the ticket. And whatever size fits a fired case well so you don't have to resize your brass as well as get as good a seal as possible. Another thing that goes a long way to helping is granular filler over an appropriate powder charge. It acts like a super gascheck and lets that boolit seal before it gets cut up by gas blowing past it.

-Nobade

[Pb2au]

That aint a throat, it's a corral!

That is a true story....

[JFE]

I believe all leverguns in pistol cals have long throats. The accuracy potential is further exacerbated because cases have short straight walls. As you have found, you can't design a bullet that meets our "usual" criteria for cast bullet accuracy and still cycle in a levergun. Add to this maybe a loose chamber where the bullet will slump towards the bottom of the chamber and you have a recipe for poor accuracy potential. Lead bullets, even ones made from hard alloy, are softer than their jacketed counterparts. Being harder, jacketed bullets are better able to withstand the vagaries of alignment and still provide some semblance of accuracy. Its more difficult to obtain accuracy with cast bullets under these circumstances.

After a great deal of trial and error this is how I approach cast bullet loads for these rifles. Firstly I use as wide a diameter bullet that will just chamber, ie the loaded cartridge needs to be a snug fit in the chamber. This way the snug fit provides alignment of the bullet with the bore.

I use a bullet that has a body that is able to reach the rifling before the base of the bullet has cleared the case mouth. In the case of the 44 mag, the throat length is around 0.22", so a body length of at least 0.25" should be sufficient. Upon ignition the bullet transitions through the throat aligned with the bore (because of the snug fit in the chamber) and remains supported until the bullet enters the rifling. When the base has cleared the case mouth, the bullet has already entered the rifling and has been supported during the transition.

Anyhow that's what I do and it seems to work.

[rpludwig]

Thanks, I'll do that!

Hmmmm, we have no member named NSB. Would that be HNSB?
Please advise.
Thank you.

NSBhttp://castboolits.gunloads.com/images/statusicon/user-offline.png
Boolit Masterhttp://castboolits.gunloads.com/images/misc/unknown.gif (http://castboolits.gunloads.com/member.php?14280-NSB)

he's been mentoring me on some 45-70 issues, and has some custom long throated (intentionally) experiences he can share...

[MBTcustom]

Thanks for the info JFE. Thats pretty much what I thought.
Do you have any thoughts on the ideal angle that the boolit should contact the throat with? (Ie matched, acute, or obtuse?)
Thank you.

[MBTcustom]

NSBhttp://castboolits.gunloads.com/images/statusicon/user-offline.png
Boolit Masterhttp://castboolits.gunloads.com/images/misc/unknown.gif (http://castboolits.gunloads.com/member.php?14280-NSB)

he's been mentoring me on some 45-70 issues, and has some custom long throated (intentionally) experiences he can share...

Crazy, hes not on our member list. Must be anotber server glitch.

[JFE]

Do you have any thoughts on the ideal angle that the boolit should contact the throat with? (Ie matched, acute, or obtuse?)
Thank you.

We're talking short range pistol cals here and in this context I don't think it matters much as long as you achieve the alignment in the first place. I have used several bullet designs and they all seem to work once aligned properly. I have a preference for a RNFP style with a wide meplat, largely because RNFP's generally feed well and the wide meplat not only kills better but that combination should further aid in alignment.

[MBTcustom]

We're talking short range pistol cals here and in this context I don't think it matters much as long as you achieve the alignment in the first place. I have used several bullet designs and they all seem to work once aligned properly. I have a preference for a RNFP style with a wide meplat, largely because RNFP's generally feed well and the wide meplat not only kills better but that combination should further aid in alignment.

Makes sense. Thank you sir!

[BCRider]

..... The Lee 429-240-2R mold I've got for a full round nose cast with the base of the nose ogive at the same size as the skirt would engage the rifling that much sooner than a SWC shape or a Kieth style.


OK, so that design looks like it engraves with a much more acute angle. Is this a design requirement for best accuracy?
Also, that boolit looks like it has only about 50% bearing surface which I would consider "no es bueno" in a bolt gun.
very strange.

I don't think it matters much at what angle the bullet meets the leade of the rifling as long as it's the rifling that has some taper or wedging action. After all the lead of the bullet is soft. And that means we are depending on the rifling to better bite into the lead and center the bullet all at the same time. And the steel of the rifling doesn't care if it's a full wadcutter, a perfectly matched angled truncated cone or anything in between. The steel of the leade will still cut into the lead and center it all at the same time. Mind you if the bullet ogive more or less matches the leade angles then the bullet will likely tend to center a little more accurately.

On the bearing surface it has two lube grooves. But they are fairly narrow so the bearing skirts seem like they are fairly typical for area. At least it's pretty typical for a handgun bullet.

Take heart. Not ALL of your rules for accuracy are voided by the long throat. You've still got alloy hardness and bullet sizing to play with.

[MBTcustom]

I don't think it matters much at what angle the bullet meets the leade of the rifling as long as it's the rifling that has some taper or wedging action. After all the lead of the bullet is soft. And that means we are depending on the rifling to better bite into the lead and center the bullet all at the same time. And the steel of the rifling doesn't care if it's a full wadcutter, a perfectly matched angled truncated cone or anything in between. The steel of the leade will still cut into the lead and center it all at the same time. Mind you if the bullet ogive more or less matches the leade angles then the bullet will likely tend to center a little more accurately.

On the bearing surface it has two lube grooves. But they are fairly narrow so the bearing skirts seem like they are fairly typical for area. At least it's pretty typical for a handgun bullet.

Take heart. Not ALL of your rules for accuracy are voided by the long throat. You've still got alloy hardness and bullet sizing to play with.


Oh I'm not disheartened! I'm learning!
My thought is this, the steel lands are going to try to deform that boolit when it hits them. We are hoping that the boolit centers in the barrel with minimum damage. Seems to me that a perfectly matching angle on the nose of the boolit will give the lands something much more supported to push against. That's my theory.

[Tar Heel]

So, with this gun you just jump to the lands. OK cool. Got it.
How do you decide what sort of nose to put on this baby? I know you want a nice taper so that it guides itself, but what's the ideal scenario? Do you match the lead angle? More acute? More obtuse?
What's you guys opinion on that?

I think you should just cast some boolits and shoot that poor rifle. Those gallon jugs of water are sneaking up on you and the cabbage heads are flowering.

:bigsmyl2:

[MBTcustom]

Actually, I shot it last night. Not too shabby! I really like it.

[btroj]

Think tangent ogive. The radius defining it will depend much on how wide a flat nose you want and how long a nose with feed thru the action.

[GoodOlBoy]

Hate to point something else out, but it dawned on me while I was working on cleaning my bench again this afternoon that I also shoot round ball loads out of my 45LC lever gun. They shoot minute of coffee can at 50 yards..... wonder what the jump to rifling is in those loads :p

GoodOlBoy

[Tom Myers]

goodsteel,

Interesting questions.
I wondered what the computer and the Precision Bullet Design and Evaluation (http://www.tmtpages.com/#TopDesign) software could tell me about making a bullet to fit and center up in the leade. This is about the only thing I could come up with.

The bullet diameter is 0.438" to fit a fired case and still allow 0.001" clearance within the chamber neck for a cartridge case with a neck thickness of 0.010".
The composite image is drawn a little longer to show the bore, groove and lead values but still indicates the overall cartridge length of your 1.575" maximum.

I don't know how this would feed through the action but, for what it's worth, this is the best I could come up with.

Hope this helps.

http://www.tmtpages.com/LinkSkyImages/forum_images/Goodsteel/A_TMT_Design_438-265-TC.Jpg


http://www.tmtpages.com/LinkSkyImages/forum_images/Goodsteel/A_TMT_Design_438-265-TC_265_gr_Sketch~~F~Cavity.Jpg

http://www.tmtpages.com/LinkSkyImages/forum_images/Goodsteel/44_Mag_GoodSteel~~A_TMT_Design_438-265-TC~Throat.Jpg

[MBTcustom]

goodsteel,

Interesting questions.
I wondered what the computer and the Precision Bullet Design and Evaluation (http://www.tmtpages.com/#TopDesign) software could tell me about making a bullet to fit and center up in the leade. This is about the only thing I could come up with.

The bullet diameter is 0.438" to fit a fired case and still allow 0.001" clearance within the chamber neck for a cartridge case with a neck thickness of 0.010".
The composite image is drawn a little longer to show the bore, groove and lead values but still indicates the overall cartridge length of your 1.575" maximum.

I don't know how this would feed through the action but, for what it's worth, this is the best I could come up with.

Hope this helps.

http://www.tmtpages.com/LinkSkyImages/forum_images/Goodsteel/A_TMT_Design_438-265-TC.Jpg


http://www.tmtpages.com/LinkSkyImages/forum_images/Goodsteel/A_TMT_Design_438-265-TC_265_gr_Sketch~~F~Cavity.Jpg

http://www.tmtpages.com/LinkSkyImages/forum_images/Goodsteel/44_Mag_GoodSteel~~A_TMT_Design_438-265-TC~Throat.Jpg

Thank you Tom, that is exceedingly helpful.
That's almost exactly what I came up with when I redesigned my boolit. LOL! That sure whips the heck out of Autocad! Looks more like Solidworks.
Bravo! You almost exactly rendered the chamber of my rifle and the situation I am dealing with.

OK, so taking the above design, we have some semblance of static fit, and its pretty well supported.
But, the barrel will be squishing that boolit down .008.
Assuming it feeds well, is this in fact the best scenario?

It was at this point that I started this thread to see. What's you guys opinion? Assuming what Tom Myers drew up feeds well in the action, Is that better than jumping a boolit such as Brad recommended in post #??

This is the reason for the thread, and the big question in my mind right now. Just because a boolit fits at rest, doesn't mean it fits in motion does it?
I welcome any and all opinions.
Thank you!

[Tom Myers]

Tim,

My only concern would be that the resizing of the bullet by the barrel might possibly deform the bullet base.

I remember when I had a 40-65 Pedersoli that required a 0.418" bullet body in order to be a slip fit in the case. The rifeling grooves were 0.408". Fired, 1/20 Tin/Lead, bullets recovered from snowbanks revealed that the base of the bullet resembled a califlour. However, the deformation was uniform and the bullets shot quite well. Much better than bullets that were sized 0.408 then bumped up by the powder explosion and then again resized down again by the leade and rifeling. The bullets sized to 0.408" also showed base deformation but the deformity was not uniform around the base, resulting in diminished accuracy.

If your rifle has deep grooves, that may be a distinct possibility but if you have microgroove rifleing, I really cannot forsee any gross deformation of the bullet base.

If you do decide to try a bullet of that design, I would bet that it would impact like the Hammer of Thor.

[MBTcustom]

Tim,

My only concern would be that the resizing of the bullet by the barrel might possibly deform the bullet base.

I remember when I had a 40-65 Pedersoli that required a 0.418" bullet body in order to be a slip fit in the case. The rifeling grooves were 0.408". Fired, 1/20 Tin/Lead, bullets recovered from snowbanks revealed that the base of the bullet resembled a califlour. However, the deformation was uniform and the bullets shot quite well. Much better than bullets that were sized 0.408 then bumped up by the powder explosion and then again resized down again by the leade and rifeling. The bullets sized to 0.408" also showed base deformation but the deformity was not uniform around the base, resulting in diminished accuracy.

If your rifle has deep grooves, that may be a distinct possibility but if you have microgroove rifleing, I really cannot forsee any gross deformation of the bullet base.

If you do decide to try a bullet of that design, I would bet that it would impact like the Hammer of Thor.


No doubt!
However, I already have a 45-70 Guide Gun if I need a big hammer. I'm actually thinking of sticking with 250 grains or less with this one, and if I can get 1.5" groups at 50 yards, then I'm happy with that. This thread was not started to help me find a boolit for this particular rifle per se', I was more interested in boolit design. Your post has given me a lot to ponder on. You're not the first one who has mentioned that the trick is to get uniform deformation rather than no deformation which is a pipe dream.

[TXGunNut]

However, I already have a 45-70 Guide Gun if I need a big hammer. -goodsteel

Awesome thread but I must take issue with that comment even though it makes perfect sense. ;-) I and a couple of like minded rifle afficianados (enablers) coined a useful phrase several years ago: "you can't have too many hog guns!". It has helped us justify many projects and field test opportunities.
Being a tightwad I would try Brad's approach first to see if it gives you the results you want. If not then Tom Myers' design using the bolt gun approach certainly sounds promising if it will feed. For some reason my accuracy expectations for a pistol caliber carbine are not very high, you may be in the process of changing that.

Carry on! This is going to be interesting.

[btroj]

How would that sucker do at 100 yards? I also wonder how well it would feed.

Tim, ever think of turning a similar bullet from brass, seating in a case, and checking the feeding properties? Don't know how feasible it is to even turn a few from a bigger hunk of lead?

[TXGunNut]

How would that sucker do at 100 yards? I also wonder how well it would feed.

Tim, ever think of turning a similar bullet from brass, seating in a case, and checking the feeding properties? Don't know how feasible it is to even turn a few from a bigger hunk of lead?


Suspect he's already doing that, or planning on it. Having a lathe and knowing how to use it takes a lot of the guesswork out of the "will it feed?" question.

[runfiverun]

design to fit and design for function are NOT the same thing.
in a levergun the cartridge becomes part of the mechanism when it is being fed into the chamber.

a rnfp with a "front drive band" [or full diameter nose] and a throat with an angled lead is the best you are gonna get from a levergun.
you don't have a lot of camming action to work with here and a tight mechanical fit on the nose diameter is achievable.
but you have to have some room to work with.
a levergun is just about the best tool for learning compromise between function/velocity and accuracy there is.

[MBTcustom]

How would that sucker do at 100 yards? I also wonder how well it would feed.

Tim, ever think of turning a similar bullet from brass, seating in a case, and checking the feeding properties? Don't know how feasible it is to even turn a few from a bigger hunk of lead?

Brad, I make steel mockups for everything I do and every design I make. Read the OP. In it I said this
I turned said boolit out of tool steel to check fit and function in the rifle.
The problem with making mock ups out of lead, is that it deforms so easily that it can lie to you about where things are actually touching, and how much.
Sometimes I make the mockups out of aluminum if I am going to be sending them in the mail (standard envelope works perfectly then) but for my own use, it's steel.
Of course, this gives me static fit only. The only way to see how things really work is to shoot them and find out, but I have a few tricks there as well (cast a 1/2" X6" cylinder and turn them on the lathe) but usually, it's more practical to just have the thing cut by one of our awesome makers (Tom at Accurate is my favorite).
Anywho, that is definitely something that I do regularly, and it gets you closer than anything else.

[btroj]

Didn't see that you already made a dummy. I suppose I'm the dummy?

At some point ya just gotta go with your gut. Run makes some good points too, he often does. This time they were even clear stated!

[MBTcustom]

So basically, you're saying make sure the boolit:
1. Functions properly
2. Is the correct diameter
3. Looks pretty
In that order, and then hope it shoots accurately. (rabbit foot in pocket, salt over left shoulder, special boolit lube made of 4 leaf clovers and holy water)

LOL!

[btroj]

Sorta?

Function is mandatory for a leveraction. No bullets that don't feed are allowed unless you enjoy single shots with a tube magazine!

Diameter is a no brainer. Well, unless you enjoy mining barrels for lead.....

I don't shoot ugly bullets. Some look better than other but I do like the way some look in a loaded round. My father in law would say they just look right. He is right every so often.

Seriously, look at something like the 640 style nose in something around 240 gr. That is the nose style I would want. I also would want that smooth transition from nose to body, no sharp shoulder drive bands.

It need not conform to the shape of the throat as long as the nose design allows it to self center and easily enter the bore.

[MBTcustom]

Sorta?

Function is mandatory for a leveraction. No bullets that don't feed are allowed unless you enjoy single shots with a tube magazine!

Diameter is a no brainer. Well, unless you enjoy mining barrels for lead.....

I don't shoot ugly bullets. Some look better than other but I do like the way some look in a loaded round. My father in law would say they just look right. He is right every so often.

Seriously, look at something like the 640 style nose in something around 240 gr. That is the nose style I would want. I also would want that smooth transition from nose to body, no sharp shoulder drive bands.

It need not conform to the shape of the throat as long as the nose design allows it to self center and easily enter the bore.

So why not match the angle of the throat within that smooth transition? What would be the harm in doing so? Or are you saying it's so janky of a design that it really doesn't matter?

[TXGunNut]

Pretty is as pretty does. Learned that when I bought a Ruger Mk I over 30 yrs ago. On top of that it thinks Winchester Wildcat is Eley Match. You're thinking outside the box, Tim. I think it's worth a try.

[btroj]

It isn't that the rifle design makes the nose taper to ogive relationship irrelevant. I just don't know that "fit" requires that precise type of fit.

I'm no engineer, bullet designer, or what not but to my mind having those angles/surfaces match exactly could be detrimental. Let's think for a second. Of those surfaces match precisely the. What happens when the bullet hits the leade? The bullet suddenly has a massive amount of instant contact. It isn't gonna self center, it has too much contact. It also suddenly needs to engrave over a large area. The base is still going forward but the front end stopped. Bullet slump can easily take place and your rifle has a huge amount of room for that to do bad things.

If we have less initial contact between ogive and leade the bullet can center better. It also will engrave easier as the bullet is initially engraving a much smaller surface. Bullet slump issues might be minimized.

Again, think of fit as dynamic, not just static. We are looking to get a bullet to center in the bore and engrave straight. We aren't looking for a fit that will hold fast like a Morse taper. We also need to think of what happens when we pull the trigger. Our bullet can, and will, change shape. We can either have that happen in a manner conducive to accuracy or let it be willy nilly.

Like I said, I'm no engineer but these are the things my experiences have taught me. I want all my lever action bullets to have this kind of "fit".

[btroj]

http://castboolits.gunloads.com/showthread.php?166506-What-is-quot-fit-quot/page2

Here is a thread from a few years ago where I asked "What is fit". Some of the discussion is worth reading Tim, it helped from my opinions and made me change how I looked at things. Most of all it made me better at observing what was going on in my barrel.

[MBTcustom]

It isn't that the rifle design makes the nose taper to ogive relationship irrelevant. I just don't know that "fit" requires that precise type of fit.

I'm no engineer, bullet designer, or what not but to my mind having those angles/surfaces match exactly could be detrimental. Let's think for a second. Of those surfaces match precisely the. What happens when the bullet hits the leade? The bullet suddenly has a massive amount of instant contact. It isn't gonna self center, it has too much contact. It also suddenly needs to engrave over a large area. The base is still going forward but the front end stopped. Bullet slump can easily take place and your rifle has a huge amount of room for that to do bad things.

If we have less initial contact between ogive and leade the bullet can center better. It also will engrave easier as the bullet is initially engraving a much smaller surface. Bullet slump issues might be minimized.

Again, think of fit as dynamic, not just static. We are looking to get a bullet to center in the bore and engrave straight. We aren't looking for a fit that will hold fast like a Morse taper. We also need to think of what happens when we pull the trigger. Our bullet can, and will, change shape. We can either have that happen in a manner conducive to accuracy or let it be willy nilly.

Like I said, I'm no engineer but these are the things my experiences have taught me. I want all my lever action bullets to have this kind of "fit".


See that is completely opposite of the way I think of it Brad. The way I'm thinking is that we are going to have to move that boolit into alignment with the bore, becasue lets face it, we'll never have it exactly right. My thought is is that since we are shooting a very soft object into a very hard hole, and since we want that object to be centered by that hole and not deformed any more than necessary, then having broader contact and as much support as possible will help it align.
After all, we are darn close. I'ts not like we are throwing a boolit in the lead at a 30 degree angle or something. It more like we are off on the angle by a few arc seconds, and we are off on the alignment by a thousandth or less and we need to get that boolit the best chance to get aligned as possible.
One philosophy is to give it a long leadin angle and gently convince the boolit to comply. Another is to give you boolit a 90 degree angle on the shoulder and let it hit the rifling like a brick going through the bell of a trombone.
Neither one of these philosophy gives much support to the boolit, and they both allow the boolit to be deformed greatly before they get it moving. Perhaps people were to busy laughing at my "boolit deformation at launch" thread to really take a close look at the pictures and see if they could see what I see with a microscope. Pay special attention to the 311466 boolit. I'll give you a hint: (the rifling in my barrel was not a gain twist).

[MBTcustom]

http://castboolits.gunloads.com/showthread.php?166506-What-is-quot-fit-quot/page2

Here is a thread from a few years ago where I asked "What is fit". Some of the discussion is worth reading Tim, it helped from my opinions and made me change how I looked at things. Most of all it made me better at observing what was going on in my barrel.

I have read that thread, and I agree with almost everything written there. That is boolit shooting 101 and has been known for quite some time here.
But that's not what you yourself are advocating in this thread, so I can only assume that you have decided that thread is an example of what not to do?
What I am wondering here, is when perfect fit is impossible, and you have to jump, and you can't very easily make the brass fit the chamber without using a boolit that is ridiculously huge for the GD, and you have to jump 1/8" to the rifling how do you achieve dynamic fit?

Telling me to solve the problem with art, is not the answer I'm looking for. I'm hoping there is some sort of guidance that is based on something a person could actually measure.
I regret having started this in Leverguns forum. I have moved it to Molds Maintenance and design forum.

[Tom Myers]

If we have less initial contact between ogive and leade the bullet can center better. It also will engrave easier as the bullet is initially engraving a much smaller surface. Bullet slump issues might be minimized.

Again, think of fit as dynamic, not just static. We are looking to get a bullet to center in the bore and engrave straight. We aren't looking for a fit that will hold fast like a Morse taper. We also need to think of what happens when we pull the trigger. Our bullet can, and will, change shape. We can either have that happen in a manner conducive to accuracy or let it be willy nilly.

Like I said, I'm no engineer but these are the things my experiences have taught me. I want all my lever action bullets to have this kind of "fit".

btroj,

Your comments pretty much sum up the concepts that define the Design Paramaters (http://www.tmtpages.com/draw/UltimateHelp/hs90.htm) of the new Cast Bullet Design ~ Ultimate software module (http://www.tmtpages.com/#ultimate).

Below are images of the design drawn by the software before I edited the dimensions to conform more to Tim's original specs.

The chamber fit image illustrates the minimum contact, maximum filling, self alignment concept inherent in the pramaters that govern the dimensions of the initial design.

The final bullet profile may be modified in many different manners and still conform to the original design paramaters.

Although I must admit that a practical, vaiable bullet designed to fit this short throat, continuous tapered lead is a challenge to both the softare and the designer.

P.S. One thing that I just realized about this design is that, as indicated on the bullet sketch, the Center of Pressure and the Center of Gravity almost perfectly coincide. Theoriticaly, this should result in a very stable, accurate, medium range, target bullet


http://www.tmtpages.com/LinkSkyImages/forum_images/Goodsteel/A_Test_Bullet_438-424-267_271_gr_Sketch.Jpg

http://www.tmtpages.com/LinkSkyImages/forum_images/Goodsteel/44_Mag_GoodSteel~~TMT_438-424-267_Throat.Jpg

[MBTcustom]

You know Tom, I'm starting to get real jealous of that program ya got there. Sure makes pretty pictures!
Thank you for doing this!

OK, so we have two theoretical options that Tom has drawn up.

One has a tapered lead in (see post#34 on page 2), and the other has a sort of scraper groove. Which one is correct if you back it up 1/8" and launch it in the barrel from afar?

[Tom Myers]

You know Tom, I'm starting to get real jealous of that program ya got there. Sure makes pretty pictures!
Thank you for doing this!

OK, so we have two theoretical options that Tom has drawn up.

One has a tapered lead in (see post#34 on page 2), and the other has a sort of scraper groove. Which one is correct if you back it up 1/8" and launch it in the barrel from afar?

Tim,
No need for you to suffer through those agonizing and debilitating pangs of envy and jealousy. :mrgreen:
All it takes is a few bucks and a little bit of your time and you too can download and enjoy the benefits of the Cast Bullet Design software packages (https://secure.tmtpages.com/catalog/index.php?main_page=index&cPath=76&zenid=545ddd4f2214dfb13562073c2ea3a2fa). :-P


If one were to "Back up" either design in the chamber, the theroetic three point alignment concept of the designs would be lost, thus allowing either or both non-concentric bullet slump or initial bullet, bore axis misalignment.

[btroj]

First off you need to realize that fit in a lever action won't be the same as in a bolt gun. Think of what Run said, no camming to push bullet into lands. Your rifle also won't feed a bullet that can fit like a bolt action could.

Look at that link I sent. Eutectic mentioned ONE way of getting awesome dynamic fit with his single shot where the bullet is pretty my entirely in the throat at ignition. Great example, not practical.

Getting good dynamic fit will require matching powder curve and alloy. It will require a bullet that can self center. Remember my comment he other day about my Marlin 357? The 640 style nose gave me better results than anything because it gave better dynamic fit. That gun has a long, but abrupt throat. Square shouldered bullets need not apply.

You are pushing a bullet into a tapered hole. What will go in easier and to straighter, a squared shouldered bullet or one with a tapered nose? Will the taper angle make much difference? I like a tangent ogive, I think it gives the best entry into the throat.

Don't forget that your bullet deformation tests were all in a different rifle with low pressure charges. Different gun with higher pressures will make the bullet far more plastic, need to take that into account.

[btroj]

You know Tom, I'm starting to get real jealous of that program ya got there. Sure makes pretty pictures!
Thank you for doing this!

OK, so we have two theoretical options that Tom has drawn up.

One has a tapered lead in (see post#34 on page 2), and the other has a sort of scraper groove. Which one is correct if you back it up 1/8" and launch it in the barrel from afar?

Don't forget to look at how those bullets will fly. Both are essentially a long wadcutter. I doubt they will give great results at ranges past 50 yards.

Feeding and downrange accuracy can't be ignored.

Trading downrange capabilities for potential accuracy isn't a good trade in my opinion unless you want a short range tack driver.

[MBTcustom]

Let's not lose focus here Brad. The whole reason I started this thread was to have a good discussion and figure a few things out. Mainly: What is the best compromise that can be made with the angles and such in order to get the best possible scenario from a lever gun with a chamber such as this.
I am very very aware that the situation in this rifle is different from a bolt gun. That's why I started the thread.
Please consider that if you don't get a boolit launched correctly to start with, it really doesn't matter how aerodynamic it is does it? I pretty boolit that misses really doesn't do much for me.

Now, I have a few 44 boolit designs kicking around the shop, and I picked one that was the closest to Tom's awesome, sexy, bodacious and incredibly kewl depiction up yonder.
Happens to be this RN Ideal I was already dinking with.

OK, so I went to the sand box and started messing with cat sneeze loads to see what I could figure out about fit.
I tuned the load so that I could stop the boolit in the throat, so I could then see if the boolit was centering itself or not. Obviously, if the first driving band of the boolit could not center itself at low pressure, there is not a snowballs chance in hell that it would do it at max speed. Just to make the test fair, I used some boolits that were cast out of a very hard WD alloy on the order of 19BHN.

What I found was that the boolit was not centered in the throat at all.
This is one side, and you will notice (OK, maybe you can't see it) that the lands cut deep enough to wipe the surface of the boolit with the grooves?
111813
Directly opposite, we see that the lands did not cut as deep, and also extended all the way down to the bottom driving band.
111814

Conclusion: That boolit entered the rifling crooked.

[btroj]

That bullet doesn't hit the rifling until it is the full diameter. What happens of the nose had a more gradual taper along the joint from more to bore diameter?
A round nose doesn't have much for self centering properties. The nose never makes any contact with anything.

Are you interested in a purely academic discussion of fitting this rifles throat or in making a practical bullet that shoots well, feeds, and has downrange potential?

From a purely academic approach Tom gave the answer. From a practical point of view it is lacking.

[MBTcustom]

Are you interested in a purely academic discussion of fitting this rifles throat or in making a practical bullet that shoots well, feeds, and has downrange potential?

From a purely academic approach Tom gave the answer. From a practical point of view it is lacking.

Aha! but academics are useless without application are they?
Academics can be used as a crutch with a bolt gun, but not with this scenario. In this scenario, academics and theory is going head to head with "the real world" and I hope to gain a better understanding of how to balance the two to produce the best possible outcome.

I already know how to get a usable load from this that will do for busting deer etc etc, but I want to use this rifle to learn about dynamic fit and how things work at launch. Nothing like this will ever be made in my shop, as I am persnickety about building superbly accurate rifles (as you are about to find out) and this is the perfect place to do some experiments.
Besides, this rifle was presented to me by Felix's family, and I feel there is no better honor I could do a rifle from that man as to use it to learn something important.
Felix did things like this. He looked closer than most people were willing to, at things that other people didn't think mattered, and he always seemed to know more than everybody else.

SO, in honor of Felix, I am continuing on. If I'm boring everybody tears, there's a whole bunch of other things to read than my little project here, but I really appreciate the time you take to discuss this and look a little deeper.
I'm not looking for a quick answer to anything. I'm trying to learn about boolit design. That's it.
Thanks!

[btroj]

Contact someone like Blammer that has a huge variety of 44 cal moulds and get a dozen or so from each. Look at how they fit and look after your sandbox test. Which nose shapes center best.

I'm sure Rick has a few designs too but his might be designed for best work in a revolver and might not be best in a rifle like yours.

Welcome to the world of leveractions. I have been fortunate to only have get real picky on me. Or maybe I just got lucky and chose the right design up front?

[MBTcustom]

I'm going to start cutting boolits out of billet lead with different nose profiles and see what I can determine.

[btroj]

If possible go shoot some at real velocities and see how they group.

[MBTcustom]

If possible go shoot some at real velocities and see how they group.

All in good time Brad. Think first. Do later. Mix those two up and you have typical results.

Exactly right Popper. I can't imagine things working better at higher velocity than they do at low velocity. Thus, the sandbox and cat sneeze loads.

[Tar Heel]

Have you shot that rifle yet or are you going to talk it to death? :-)

[TomAM]

I just finished working up a design for my new Browning model 92 44 mag, and post #22 here mirrors my findings.
"Support" basically means that the boolit needs to be pointed exactly in the correct direction upon chambering, and since you cannot feed what is essentially a shallow seated wadcutter in a lever gun, you won't be getting any support (upon chambering) from lead engaging barrel steel. The only way left to improve alignment is with a boolit diameter that fattens up the case mouth and takes the rattle out of the cartridge fit.
When there's boolit jump, and the boolit can tilt at all when launched, the matching of nose angle and throat is meaningless. The force driving it forward is far greater than the force that's later imparted by the throat to realign the boolits path. The boolit just deforms.
Static fit must be the top priority, and in this situation the fit can only be achieved through the neck of the loaded cartridge.
So personally I use my #43-240A with a large diameter body. The nose has to be lever function friendly, and this one is.

[btroj]

Agree entirely Tom. The 43-250M looks good too.

A leveraction is a pile of compromises.

[MBTcustom]

Makes total sense. Fit is King. Size is not.
BTW Tom, I purly Looooooooove this new mold you just sent me. You're my favorite maker.
Love ya
Mean it.
LOL!

6 day turnaround and the best casting mold I've got yet. That's.......amazing.

[nanuk]

I remember reading about the shutzen (sp?) guys who would make a bullet the EXACT shape of the leade/throat, seat it into the throat, put a powdered cartridge in behind and shoot tiny groups....

makes me wonder about the comment above re/ resistance and deformation....

[btroj]

Tim, I hate to say this but you know who to ask.

[Nrut]

Makes total sense. Fit is King. Size is not.
"Size" ​is part of "fit"..

[MBTcustom]

Tim, I hate to say this but you know who to ask.

Yes I do.

I need to ask my rifle.

[btroj]

Yes I do.

I need to ask my rifle.

not what I meant but that made me laugh.

[MBTcustom]

I can't afford not to.
LOL!

[MBTcustom]

Have you shot that rifle yet or are you going to talk it to death? :-)

Oh yes! I've shot it with boolits from an old Ideal RN. Got about 1.5" groups at 50 yards judging by the rocks. LOL! Just the maiden voyage. I'm rounding up all my 44 brass and I've cast enough boolits to keep me in bidnes for a while. This baby will be with me in November.

[TomAM]

I remember reading about the shutzen (sp?) guys who would make a bullet the EXACT shape of the leade/throat, seat it into the throat, put a powdered cartridge in behind and shoot tiny groups....

makes me wonder about the comment above re/ resistance and deformation....

Schuetzen shooters know that the only way to take advantage of that perfect fit is to have the boolits fully engage the leade before firing. That's why they load the rifle in that manner. A nose which perfectly matches the leade is useless if it is allowed to flop around upon firing before engaging the leade. When exposed to 35,000 psi, the boolit does not pause to re-align itself with the bore. It just mashes into it, while tilted. The only reason that we strive for fit is because fit provides guidance.

[TXGunNut]

I regret having started this in Leverguns forum. I have moved it to Molds Maintenance and design forum.-goodsteel

Glad I found it again. Nothing to offer, lots to learn.

[TXGunNut]

Two questions: Do you know what Felix was loading/casting for this rifle? Could be an interesting read if he posted about it. Second may sound obvious but sometimes we have to step back and ask; what are your goals/expectations for this project?

[MBTcustom]

Two questions: Do you know what Felix was loading/casting for this rifle? Could be an interesting read if he posted about it. Second may sound obvious but sometimes we have to step back and ask; what are your goals/expectations for this project?

The goal is to learn something by exercising the mind.
The trick of fitting the chamber is awesome. I'm remeasuring my pound cast, and I'm going to turn a new dummy to try and see if it feeds. I'm still pondering making it so that I hit the throat at the same angle.
Seems we have the back of the boolit trapped with the brass fitting tight in the chamber. Seems to me that if we want that boolit to launch forward and be supported from the nose, while the base is still in the case neck, then having the exact same angle up front would be helpful.

[Doughty]

A couple years back I played around with the same question. I had several Ruger single actions, a Smith N frame, and a Marlin lever, all in .45 Colt. I wanted one bullet and one load that would work good in all of them. The Marlin chamber and barrel is apparently what is typical; .452 groove diameter and a chamber that is large in diameter and length. I made a swaging of the Marlin chamber. You might be able to see in the picture that the grooves go right up to the case mouth. The case diameter at the mouth is .474, the diameter at the start of the tapered throat is .469. This tapers down to .453 and a slug through the barrel was .452. How they did that I don't know. The point is that my chamber is very similar to yours in general design.

I had a Lee 255 grain bullet that cast at about .452. It shot OK at slower speeds, but started losing it as velocity increased. I made a series of several molds trying various things. In general, I found that as the bullet got bigger in diameter and longer in length, the better it shot. I can just get a cartridge at 1.675" to work through the action. Fortunately this would fit it all the revolvers. I could get a bullet of .461 diameter to easily chamber in the rifle and this gave the best accuracy, however one Ruger would only take a maximum of .457 diameter. Again, fortunately, this still shoots pretty good in the rifle.

The other thing I found was that, the more full diameter area I could get in front of the crimp groove, the better it was. Again, the limiter here was in the revolvers. The full diameter length is also such that the front has a good start into the grooves before the end leaves the case. The design principal seems to me to be pretty simple. Fill up with lead, as much of the neck, throat, lead, grooves and bore as you can, trying to keep the center line of the bullet as close to the centerline of the barrel, before it is fired, and for as long as you can, after it is fired.
I made two four cavity molds to keep them all going and load on a Lee Loadmaster. The Loadmaster took a
little tinkering with to handle these odd .45 Colts. In the first station, the de-priming station I use a Lee carbide sizing die with a de-cap pin in it. I used a diamond point on a toolpost grinder to open the die up so that it would only size the over expanded rifle brass as much as was necessary to go into the revolvers. In the second station, the priming station, I sized another Lee carbide so that it would only neck size the brass enough to firmly hold the .457 bullets. The standard Lee powder through die worked fine to bell the mouths a little and the standard Lee seating die worked okay to seat with. The last die is one of Ranch Dog's rifle type Factory Crimp Dies for the .45 Colt, which does in fact crimp the finished round.

As Phil would say, "Happy, happy, happy."

112034

[MBTcustom]

Wow Doughty, I thought you left us to our own devices! Good to see you sir!

It seems that you have summed up and put nails in the general consensus. This thread has given me a lot to think about.

It appears that I was wrong. Here I thought that dealing with a chamber like this would require a different philosophy, but instead, it's exactly the same as a normal bolt gun. We're just getting there a different way.
Thanks everybody for weighing in!

[TXGunNut]

Thanks everybody for weighing in!-goodsteel

Thanks for the mental gymnastics, it's been very educational.
I always wondered why pistol cartridge leverguns had chambers with such a long leade. Only theory I've come up with has something to do with their black powder heritage. Figured maybe the long leade was to keep powder & lube residue a place to build up a bit and still allow rounds to be chambered. Don't know if that's true or if it will help improve the fit but sometimes the history of an issue helps with the solution.

[MBTcustom]

Thanks everybody for weighing in!-goodsteel

Thanks for the mental gymnastics, it's been very educational.
I always wondered why pistol cartridge leverguns had chambers with such a long leade. Only theory I've come up with has something to do with their black powder heritage. Figured maybe the long leade was to keep powder & lube residue a place to build up a bit and still allow rounds to be chambered. Don't know if that's true or if it will help improve the fit but sometimes the history of an issue helps with the solution.

You know, I'm not really convinced they have a long lead. It's just that they have no step in front of the case mouth like a bottle neck does and instead start their lead in taper at the case mouth diameter. As the trig goes, for every thousandth of an inch you gain in diameter, you gain gain .018 in length of the lead. So it's kind of a trick. Most of the lever guns I have worked on have pretty obtuse angles on their leads, but that's offset by the fact that the throats are starting out at the neck diameter. Not the groove diameter.

[runfiverun]

actually it's closer to a semi-auto handgun/rifle.
if you look closer at the pictures tom provides and focus on just the throat area, you'll see where brads boolit picture coincides with the nose shape and the throat shape.
we are trying to achieve a mechanical throat fit on the run.
it's a similar principle to a bolt gun where we back the fitted boolit [or tune a load by oal with a jacketed bullet] out of the throat slightly and speed up the powders burn rate to gain velocity.
we don't want the initial pressure spike from [and from using a tooo slow powder rate] jamming the boolit into the rifling any longer, we now need a bit slower rise before contact then the spike from engagement.

Tim:
remember the phone conversation we had a bit back about starting things out as straight as possible to begin with?
we can't get to 100% here due to other issues [oal, feeding, whatever] so we have to get as much as we possibly can from every angle.
we go as far as possible before damaging the base of the boolit by sizing it to the barrel.
even doughty's post showed a little less than optimal throat diameter still shot well.
however he still needed a .005 oversized boolit to hold everything straight enough.

now if he could have gotten the centerline alignment without damaging the base upon firing I'd bet his accuracy would have gone up too.
you'd be amazed what a single wrap of .002 cello-tape can do.

[MBTcustom]

But Nolan, you can't put tape on your brass. There's a law against it or something. LOL!
That's a good way to reduce your Boolit size requirement by .003 right off the bat.

[btroj]

Dang it Lamar, did you change your name again?

[runfiverun]

ghost writer,,, I'm a busy man..:lol:

anyway I learned a lesson from our government waay back during the shuttle missions.
they spent something like 114 million dollars developing a pen that would write in outer space [that's where GEL pens come from]
the Russians spent 10 cents at the local elementary school and use a pencil.

[btroj]

You are a busy man.....

Nice story about over thinking......

[MBTcustom]

There is no such thing as "over thinking". The brain is like a muscle. It takes work to make it stronger. Which probably explains why so few enjoy using it! (No direction toward present company. It's just a quote I heard somewhere)
In contrast, the above is an example of gross over engineering.

[runfiverun]

over thinking things sometimes gets in the way of seeing things clearly.
what we call the dumbest smart guy syndrome in the patch.

it's why I recommend taking a pound slug of your throat and then outlining it on a piece of paper and just sitting there looking at it for a while before making a second step.
you'll start to see a picture of what you should be looking at in terms of a real functioning boolit before too long.

[btroj]

Overthinking is possible. Don't try to find such an elegant solution that you pass up on many quite workable, very doable, very good designs.

Good enough is good enough. Trying to find perfect can drive a man crazy, and get expensive.

Don't believe a solution can be overthought? Ask Rube Goldberg, he knows a thing or two about it.

[Tom Myers]

over thinking things sometimes gets in the way of seeing things clearly.
what we call the dumbest smart guy syndrome in the patch.

it's why I recommend taking a pound slug of your throat and then outlining it on a piece of paper and just sitting there looking at it for a while before making a second step.
you'll start to see a picture of what you should be looking at in terms of a real functioning boolit before too long.

About 5 years ago I came to the same conclusion. I had already developed the Precision Cast Bullet Design (http://www.tmtpages.com/#Advanced) software to the point where a bullet design could be accurately designed and evaluated. I was determining the dimensions of the bullets almost exactly as you suggest - on paper. The designs were fitting and working well but a final design consumed many hours of work with constant re working due to simple math errors and the inability to sketch the chamber accurately to scale.

The next logical step was to develop a Chamber Drawing module (http://www.tmtpages.com/draw/UltimateHelp/hs110.htm) that could produce an accurate scale drawing of a specific chamber from a database of dimensions determined from a pound slug or chamber cast. That worked well and cut the time required for a useable design almost in half. But it still required utilizing existing Windows imaging software to overlay and manipulate the placement of the bullet design within the sketched chamber throat-leade area.

Two more modules were needed to really construct repeatable, accurate designs that actually worked. First the database driven Cartridge Case drawing module (http://www.tmtpages.com/draw/UltimateHelp/hs140.htm) was developed and then finally the Overlay module (http://www.tmtpages.com/draw/UltimateHelp/hs130.htm).
Now all the units could be accurately dimensioned and those dimensions stored in databases where each individual drawing module could retrieve those dimensions then draw and store on the computer, a scaled, dimensioned sketch of the chamber, cartridge and bullet used fore each design.

The four design modules, Chamber, Cartridge, Bullet and Overlay, made it possible to retrieve and display the drawing of each unit in a composite drawing that allowed accurate movement of both cartridge and bullet within the chamber to achieve the desired design.

Now things were working really well and practical, useable bullet designs could be designed for nearly any chamber and cartridge combination. However trial bullet designs still needed to be determined by pen and paper calculations, with the resulting rejects, until a useable design was achieved.

The last, but probably not the final, step in the on-going project was the Cast Bullet Design~Ultimate module (http://www.tmtpages.com/#ultimate). This unit access each database for critical dimension values and then determines an initial bullet configuration conforming to pre-determined design parameters (http://www.tmtpages.com/draw/UltimateHelp/hs90.htm). Those parameters are partially editable before the values are actually exported to the Bullet Design module for final editing so the number of reject designs has been nearly eliminated.

Throughout the entire process, the ultimate goal has been to allow anyone, with average computer skills, the ability to construct a practical bullet, designed according to known proven parameters, that dimensionally fits a certain chamber. A comprehensive sketch of that design can then be sent to a mold maker with a reasonable certainty that no more designs and molds need to be cut before finding one that actually works.
After many, many hours of writing extensive help manuals (http://www.tmtpages.com/draw/UltimateHelp/DesignUltimateHelp.htm) and context sensitive help hints, I believe that goal has been reasonably met.

Although the software doesn't appeal to all, it is just another tool to aid in our quest for more functionality and accuracy from our Cast Boolits.

[MBTcustom]

Really ingenious Tom. I love it!
As soon as I can get together enough scratch to take care of the itch, im going to do just that.
This thread is actually a pretty impressive demonstration of the power of your program.
Gotta give you an internet high five!

[runfiverun]

I'm using the older bullet design pro.
it has some frustrating features..
but will draw a reasonable boolit if I use my head about what I really want.
the paper thing really helps me because I'm not reasonably computer literate :lol:
so I have to think things through on how a boolit throat relationship is going to actually work.
a static [non moving] mechanical fit is a whole different thing compared to a moving mechanical fit.
leverguns and pistols are almost a total loss when it comes to a static mechanical fit so you have to look for the moving mechanical fit as part of the working compromise.

[MBTcustom]

I'm using the older bullet design pro.
it has some frustrating features..
but will draw a reasonable boolit if I use my head about what I really want.
the paper thing really helps me because I'm not reasonably computer literate :lol:
so I have to think things through on how a boolit throat relationship is going to actually work.
a static [non moving] mechanical fit is a whole different thing compared to a moving mechanical fit.
leverguns and pistols are almost a total loss when it comes to a static mechanical fit so you have to look for the moving mechanical fit as part of the working compromise.

See, that's the whole reason for the thread. I mean, if you are talking static mechanical fit, that's where I live!!! I have taken that to levels that most people will never achieve (no brag, just fact, and I'm lucky to have the machinery to make it happen) but what happens when things start moving, exploding, turning, engraving, slumping, and harmonizing? Well, I'm pretty much lost, but I'm trying to catch up.
I'm shooting into a box of sand at cat sneeze levels to try to learn the basics, because here in Arkansas, we don't have nice powdery stuff to shoot into at long range. Here, you're shooting into rock laden mud which means your boolits are either lost, or severely damaged.
I thought about building a crumb rubber trap, but I just don't have time to do it, nor do I have property to shoot on where the patrons don't mind having crumb rubber strewn all over the place, so the only way for me to see a lot of boolits that got shot (albeit at 350 FPS) is the sandbox.
Now, what I have seen has been educational! I see boolits twisting as the lands engage the front of the boolit and the rear catches up. I see improperly fitted noses skidding as they engrave the rifling, I see fins being wiped into lube grooves as the lands ride over them, I see rifling's that are deeper on one side than the other. All kinds of cool stuff, and I theorize that the boolit might be launching into the throat at very similar speed as it does at high velocity. I mean that boolit doesn't just start moving. It takes an inch or two of barrel to get up to speed, so I'm thinking that it might not be that different to the nose of the boolit whether it's being pushed by 2 grains of Bullseye or 45 grains of 4895.
I'm fixin to find out if all that matters on paper at higher velocity. I have managed to find a boolit that fits better.

But this little rifle here really made me think about dynamic fit, because I don't have my perfect chambers to use as a crutch. Very interesting!

[Pb2au]

A camel is a horse designed by a committee. It is my favorite example of over thinking. It is possible to desire so many specific things, you can often overlook the most basic elements that are the key to success.
This is an excellent thread by the way. Absolutely filled with great info. Thanks to the contributors for their time.

[dkf]

Maybe if you could find a good gunsmith they could rebarrel the lever gun for you.:kidding:

[runfiverun]

wow,,, now I gotta go get a towel...:lol:

this is where it gets a bit confusing.
you get to see an actual boolit with your trap but it's not under actual conditions.
your doing a simulation.
I think you can simulate several parts of the sequence through alloy manipulation and pressure matching but you can't quite get 100%.
you can however make some good observations [hopefully notice some trends] and use those to make a logical leap...
you'll be able to see what happens with a fast pressure spike slapping a dead soft boolit forward suddenly and why that's a bad thing for sure.
you'll also be able to see what happens with a normal off the shelf mold that doesn't quit fit the throat right and observe the difference between it and one with the correct mechanical support.

[runfiverun]

ohhh one more thing that will help.
mark the boolit and case and use chamber alignment techniques, then you'll see a bit more of where on the boolit it's getting the damage.
bottom, top, whatever, that will help you with the centerline picture...

[MBTcustom]

wow,,, now I gotta go get a towel...:lol:

this is where it gets a bit confusing.
you get to see an actual boolit with your trap but it's not under actual conditions.
your doing a simulation.
I think you can simulate several parts of the sequence through alloy manipulation and pressure matching but you can't quite get 100%.
you can however make some good observations [hopefully notice some trends] and use those to make a logical leap...
you'll be able to see what happens with a fast pressure spike slapping a dead soft boolit forward suddenly and why that's a bad thing for sure.
you'll also be able to see what happens with a normal off the shelf mold that doesn't quit fit the throat right and observe the difference between it and one with the correct mechanical support.

Exactly. That's all I'm trying to do. Just because it's not the same, doesn't mean it has no value. I mean the boolit still has to jump, and it's still got to engrave, and my thought is that if it's entering the rifling crooked at low speed/high pressure, that is not going to improve with a full pressure load. Of course, I realize that I could get something that looks great in the box that doesn't do worth a darn at full pressure, but that doesn't mean it has no value. I'll take something similar that I can measure any day over something that is exact that I can't. I'm trying to see something that can't be seen. I've thought up a bunch of different ideas, but this one is the cheapest, and easiest, so I'm trying it out for a while to see if there is anything I can glean from it. I'm prospecting.

SO far I have learned that something that does bad at full pressure does bad in the box as well and something that does well at full pressure seems to do well in the box also, but I am a long way from proving to myself that the results correlate or to what extent they do or where.
It costs me nothing, and it's possible it might help. So why not observe, measure, and document?
It's a nice thing to do whilst taking a break to smoke a cigar. LOL!

[runfiverun]

yessir.
oh and don't do it down in the basement.
the wife get's mad when you knock the dust off the rafters down there. [especially if she is standing directly overhead drinking a soda]

you could pull up some of 303 guy's posts and see what results he got with his drum/rag trap and some of the things peter got to work in a couple of his rifles.
we pm'd forever back and forth about a couple of things that worked, and some that never should have worked but did just because of fit.
the waxy dip lube might be of interest to some too, it is the ultimate time saver because no sizing is done.
and the lubing is done after the round is loaded.
it goes along here in parallel lines pretty well.

[MBTcustom]

yessir.
oh and don't do it down in the basement.
the wife get's mad when you knock the dust off the rafters down there. [especially if she is standing directly overhead drinking a soda]

you could pull up some of 303 guy's posts and see what results he got with his drum/rag trap and some of the things peter got to work in a couple of his rifles.
we pm'd forever back and forth about a couple of things that worked, and some that never should have worked but did just because of fit.
the waxy dip lube might be of interest to some too, it is the ultimate time saver because no sizing is done.
and the lubing is done after the round is loaded.
it goes along here in parallel lines pretty well.


Well, I must confess, I have swapped PM's with Peter a long time ago as well and asked a lot of questions about his test tube.
I don't intend to take it as far as he did, but I do think there is something to be learned from it. I'm just using it to help me get my head around what happens to a boolit at launch.
I keep racking my brain trying to figure out how to catch a soft cast lead boolit fired at 2400fps out of an 8 twist rifle, and do it so that I can see the part of the boolit that engraved the rifling.
I have studied on some difficult problems in my time, but that seems to be about like trying to catch a ray of sunlight. Wish I had an answer.
Anyway, this is about as close as I am liable to get and even this is almost enough to wipe out the engraved nose of the boolit.

[runfiverun]

bestest boolit catcher ever..........snow.
I know it's in short supply there.

[MBTcustom]

Yeah I read about that. Unfortunately, the only predictable snow around here is in those little snow cone stands that are on every corner, and those people have no appreciation for science!
LOL!

[PWS]

Great thread!

FWIW, I had Accurate Tom cut a mold for my old .338WinMag. While not a lever gun, Winchester spec'ed another one of their giant funnel shaped throats and with ~4k rounds through it, there's a lot of space in front of the case neck. Tom's seminal suggestion was "any lead not in contact with steel is a detriment". So, we ended up with a bullet diameter of 0.345" and a "bore riding" nose that filled as much of the throat as possible (AM#34-230B). (Tom also suggested .348 gaschecks - he's smart!)

The question was poised early in this thread about how big a bullet can be forced into a certain barrel? I don't know the ultimate answer but the only significant problem running 0.007" oversized in this rifle is that load development is BORING. Practically everything shoots as well as j-wonks.



We're definitely interested in the results you get with your turned and fitted slugs!!

[PWS]

BTW, where is that sticky regarding what Accurate Mold did you design....:wink:

[Bounty Hunter]

can anyone give me info on buying conical bullits for a 1858 Remington without any fitting problems please?

[runfiverun]

those don't work like that.
they have a hollow base that bumps up..
wait.. what kind of 58 Remington are we talking about?

[btroj]

The kind made in 58, by Remington.....

I was thinking an 1858 Remington revolver but I could be wrong.

[runfiverun]

I was thinking rifle/musket...whatever, then remembered the revolver.

[MBTcustom]

I'm thinking a cap'n'ball revolver. They did shoot conicals on occasion. However, I have never used them nor seen them for sale. I grew up on an 1861 confederate navy brass frame, but I only ever shot round balls in it. I've never run across anybody selling swaged bullets nor molds that provide a HB.
However, Lee makes a mold that casts a plain base bullet.
Gotta be a HB?

[Enyaw]

Why not a hollow based bullet that can open and center better in the wicked un-throat? Couple that with a bullet full diameter as close to the lands as possible.....very short ogive-nose.

What about having the rifle re-barreled with a proper chamber? What about the same barrel rebored to a larger caliber and rechambered with a proper chamber?

I suspect the throat may be like it is to accomodate blackpowder. That or for ease of chambering-feeding in the lever action.

Jacketed bullets may fire much better in the rifle as it is.

Unheard of ??........why not ream the lands where they begin with a slight funnel with no lands till the bullet is centered in the bore? You know......funnel the bullet to the center and then the lands begin.

A reamer would need to be made to pilot on what is already in there but the cost shouldn't be too high if a tool and die maker could be found that could under stand what you were wanting. Thast would make fer a longer "jump" but jumps aren't all bad. Some gas would get by till the bullet centered in the bore as the funnel tightened on it and centered it.

The barrel could be re-sleeved or lined with a sleeve the same caliber and a proper chamber put to it. Older barrels get relined all the time.

[runfiverun]

I remember someone making a 44 cal hollow base mold. [lyman?]
I even thought about buying one I seen once.

in this case I'd check with buffalo bore and see what they have to offer.

[Enyaw]

An old cowboy and a injun sat by the fire racking their brains on how to help the horse with a camels hump and two broken legs. After a few hours of thunkin on it and emptying a coupla bottles of whiskey they got up from the fire and shot the horse in the head before they turned in and went to sleep.

Anywhoooo......when gas expands it gives equal pressure in all directions. The bullet not mechanically fit to the chamber may well be staying somewhat supported in the loose places by the gas pressure. At least for a milla second while it's at that position.

I got my brothers Rossi lever carbine shootin danged well by using soft lead bullets pushed in the range of 2/3rds from min. towards max. from the load book. Wasn't a long range target gun but could wack a ground hog at 100-150 paces well enough.

I learned from my own experience that sometimes the solution to a problem is so simple it can be over looked.

Back in the day I'd imagine the bullets were pure lead. The buffalo hunters liked the softest lead they could get because it mushroomed some. Maybe a pure lead bullet at the possible velosity and pressure would obsturate where it could and swag into the rifling the best it could and slump some to end up with a base parallel to the centerline of the bore and sorta reform to shoot well enough by not yawing much. Yawing causes the bullets to corkscrew thru the air and that's an open group but if the soft lead bullet can form itself better from a chamber that was originally made fer blackpowder and the fouling it has then maybe the yaw is minimized and the rifles can shoot accuratly enough for their purpose.

I'dbe a thunkin...if the chamber can't work because it's made wrong according to all the basic known facts then it makes no sense to try to make a bullet that's wrong to match the wrong chamber and hope to come out with two wrongs that make a "right". I'd use the rifle as is with sammi spec ammo and if it didn't do well enough I'd rebarrel or sleeve the barrel or trade it fer a bolt action rifle.

I should add that the lever action with the way the cartridge is shoved into the chamber the funnel to the chamber without a normal throat is probably the best way to get reliable feeding. Just like the military chambers of full auto weapons have a generous chamber. Reliable feeding.

That said I'd be thunkin that a sammi spec. 44 bullet would work well enough so a special mould /bullet isn't needed fer the lever rifle. Just the realization that if used within it's limits the rifle will do well enough with the chamber it has.