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

[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.

NSB
Boolit Master

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]

NSB
Boolit Master

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.

[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

GoodOlBoy

[Tom Myers]

goodsteel,

Interesting questions.
I wondered what the computer and the Precision Bullet Design and Evaluation 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.

[MBTcustom]

goodsteel,

Interesting questions.
I wondered what the computer and the Precision Bullet Design and Evaluation 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.

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.