Testing bullet base designs ?

[Hammer]

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Be it so moved that we need to test cast bullet base designs.

Using the original Keith 44 caliber mold as a starting point...

One model will be per Keith's original flat base.

One will be a bevel base like most commercial cast bullets, e.g., Oregon Trail.

And the third model will be a gas check version.

Everything else in the bullet design will be the same.

We will have LBT build three sets of four-cavity molds of each model to test to assure there is not something unique to a specific mold unrelated to the bullet base design.

We will use virgin bullet metal certified by a foundry with 8% antimony and 4% tin.

We will use Keith's Hercules 2400 powder charge.

We will need to load a thousand of each for testing.

Will need a new Dillon Super 1050 for loading the ammo.

We will need at least twenty new Ruger Super Blackhawks and an equal number of Redhawks. (Can a Ruger Forum experiment get some 1950 vintage S&W 44s too ?)

It will take some time so we will need a paid leave of absence from work.



Where do we send the bill ?



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[J Miller]

I'll take the plain base Keith bullets s'il vous plaît!
I've had my fill of bevel based bullets and no longer buy them.
I also have no need of a gas checked Keith bullet. They don't need to be pushed that hard to work as intended.



Joe

 

[btrumanj]

Funny thing about bevel based bullets. I know the flat base are mo' better because everyone tells me so but usually what's available in my area or occasionally when I order from Midsouth or Midway is bevel base. They seem to shoot pretty darn well in my guns and leading is not a big problem.

 

[Hammer]

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Hint Hint


Obama funded research grant to shoot guns paid for out of Stimulus money and NSF grants. Guaranteed renewable in seven-figures forever. Unaccounted for Stimulus money to buy toys and more toys.




Which should we study first ?

The flat base, the bevel base, or the gas check ?

The United Nations council on Other Stuff is needing these results immediately to add to an appendix on Global Other Stuff -- Part XVII. The next subcommittee meeting is in Honolulu in late February.




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[Jimbo357mag]

Do a hundred of each and get back to us with the preliminary results so we can decide if it is worthwhile to proceed with the program. Even though I don't usually shoot cast I will gladly help my country out and shoot my fair share if you want to ship some to me. :shock:

...Jimbo

 

[pps]

I have shot beveled base bullets once and it leaded (this was even after I firelapped my bore).

I'll get the qualitative post-mortem boolit analysis going here.

Cheap 5% antimony lead swagged boolits from Hornady. Minimal leading, even at magnum velocities. The ones pictured below were only driven to 850 fps.

Here's an lbt 185gr pushed to 1250fps 3% antimony, 2% tin and heat treated to BHN of 21 (beartooth bullet) There was minimal leadding, however...this was AFTER I firelapped a constriction out of the bore. This was sized by Beartooth bullets to .359" (.002" over bore diameter) I'm confident a plain base version of this bullet would NOT lead.

In the last pic is the Lymann 358156 gas check with scrap range lead and some tin for fillout, hollowpointed and pushed by 14.0 grains of 2400 @ 1250 fps. It performs comparable to the jacked factory counterparts. As you can see...the gas check didn't help much since the barrel was leaded (from constricture of the barrel squishing the lead AROUND the gas check)

It seems that fit to the bore and matching the hardness to the pressure seems to have more of an effect on leading than does a gas check.

OK, where the hell is my earmark? lol

 

[Bucks Owin]

PPS, I've used the Hornady swaged .45 255 gr to 1150 fps, both with and without a Lee liquid alox coating. Minimal leading either way. I think those bullets obturate easily and seal well. (Plus, they're .454" :wink: )As you said, FIT is the key, not high BHN, "voodoo" lube blends, etc. Most of the time, a GC is not needed at handgun velocities, and is nothing but a band-aid on the wrong alloy or size IMO. Besides that, the dang things are getting as expensive as primers! JMO, Dennis.... BTW, nice photos!

 

[pps]

PPS, I've used the Hornady swaged .45 255 gr to 1150 fps, both with and without a Lee liquid alox coating. Minimal leading either way. I think those bullets obturate easily and seal well. (Plus, they're .454" :wink: )As you said, FIT is the key, not high BHN, "voodoo" lube blends, etc. Most of the time, a GC is not needed at handgun velocities, and is nothing but a band-aid on the wrong alloy or size IMO. Besides that, the dang things are getting as expensive as primers! JMO, Dennis.... BTW, nice photos!

Thanks bucks. The gas check thing is a band aide for other problems. And you are right about the things being expensive.

I'm planning on having a custom mold made based off the beartooth bullet pictured above, but with a plain base. Likewise, I'm going to eventually have my machinist grind off the tab in the molds that make the gas check shanks on my 358156 and my 30-30 mold the 311041.

I'm confident I can get the right combo of sizing, bullet hardness, and chamber pressure to keep leading at bay...without the gas check. If I ever cast for the hornet, or the 22-250 I'll probably delve into paper patching...which appears to be another addiction in it's own right. Almost a cult, in fact.

 

[Sonnytoo]

I've used bevel-based with no leading. I've talked with two bullet companies and they say there's no leading and no decrease in accuracy. I seldom shoot at 25 yds, can't see that well with these glasses, so don't know. Certainly, they're easier to load, but I don't care about that if they don't group well.
Sonnytoo

 

[Bucks Owin]

A couple years back, when I was shooting a lot of .44's in the ol' FT, I bought a Lee 310 gr GC mold to play with some heavy bullet loads. Didn't much care for the accuracy results or the mold itself and I "milled" off the GC portion of the mold to end up with a 262 gr PB bullet. Never got a chance to play with it as I sold the .44 FT and M-29 that were the vehicles! I was hoping for a hard hitting silhouette bullet I could shoot a LOT of without the hassle of GCs. Guess I'm gonna have to get another .44 just to resume the testing! :wink: Anybody else ever cut up a Lee GC mold to eliminate the GC? How'd it work?

 

[pps]

One other thing I've done with mixed success is to take ww+2% tin, size the bullets, then anneal the lead at 420deg f for 2 hours then pour ice water into the pan to heat treat only up to the level of the crimp groove...thus leaving the tip soft for hollow pointing but hardening the driving bands in order to allow the bullet to be driven hard.

I have a bit of work to do to master this. I have had issues with the bullet breaking up if the hollow point is to deep. It is starting to look like I should be hollow pointing no deeper than 1/3 the length of the nose of the bullet.