How hard is *too* hard?

[S.R.Custom]

Have any of you guys experimented with really hard alloys?

I have a .45 LC S&W 25 with pretty shallow rifling, and accuracy with water quenched wheel weights has been only a sometime thing. (The 250 gr LSWC bullets are sized .002" over throat diameter, and the throats are .001" bigger than the slugges groove diameter.) I've noticed that the harder the alloy, the better it shoots; it seems the harder alloys get a better purchase on the rifling.

For what I use this gun for, terminal bullet performance means nothing, but accuracy is paramount. How hard can you make bullet alloy before there are problems? What are the problems?

[xr650]

I am under the impression that softer alloy and push harder to grip the rifling better. (I would use that obtur??? word if I knew what it was. [smilie=1:)

Is this not always the case?

[JIMinPHX]

Yea, you need a boolit that is soft enough to get good obturation for the riffling to get a good grip on the boolit. But if your riffling is shallow, then the alloy needs to be a little extra hard so that it will not just shear off & turn to goo. The rule of thumb that I’ve been told to go by is BNH x 1440 = PSI. If that is the case, then a 14,000 PSI (max) .45 Colt cartridge would want a boolit with 14,000/1440 = about 9.7BNH. I don’t know how much further you can go before you run into trouble. I’ve probably gone about 1.5 times that hardness formula before without problems, but I haven’t pushed it past there. If you were able to recover your fired boolits in good condition, then you could look for signs of gas cutting or incomplete obturation. I would expect that those would be the problems to watch for, but I’m not sure about that.

[Bass Ackward]

Have any of you guys experimented with really hard alloys?

I have a .45 LC S&W 25 with pretty shallow rifling, and accuracy with water quenched wheel weights has been only a sometime thing. (The 250 gr LSWC bullets are sized .002" over throat diameter, and the throats are .001" bigger than the slugges groove diameter.) I've noticed that the harder the alloy, the better it shoots; it seems the harder alloys get a better purchase on the rifling.

For what I use this gun for, terminal bullet performance means nothing, but accuracy is paramount. How hard can you make bullet alloy before there are problems? What are the problems?


Ever wonder why one guys swears at soft bullets and another swears at them? :grin: Why one guy says one design is crap and another loves it? :grin: Ever wonder why we keep making the same mistakes over and over again? (I do)

Accuracy problems from too hard of a bullet? Yes and no. We would have to agree on definitions to agree on the correct answer. Can you create other problems? Sure, but that isn't the hard bullets fault. What problem are you fighting to cause you to go so hard? Is the diagnosis of low rifling height correct? My 25s probably got the same thing and I haven't shoot anything harder than ACWW maybe ever in those.

My best accuracy seems to always occur just before leading begins or just as it is. That means just exactly as the pressure is causing the gun to begin to destroy the bullet. It is a combination of hardness, bullet design that also includes weight, lube quality, pressure, and rate of pressure increase. It's a balancing act where the rate of pressure increase is as important as the over all pressure because at some point you must fight ignition issues if you go too slow on the burn rate chart. And sometimes too slow for a soft bullet is higher up than logic would dictate if you are holding pressure down. Powder needs pressure to burn.

So if you accept my premise above, and you maintain Colt pressures, then you do eventually reach a point where the above CAN'T happen because it can't do what needs to be done. And as general rule is that the harder I go, the smaller in diameter I want to be too which sounds bass ackward. That could also be an issue, but you would know the gun better than me. ACWW ought to work just fine here.

You will hear someone else say, "Match your hardness to your pressure." That is a simplified statement of mine as it over looks the variables. One guy can beat the variables with 10 BHN while another needs 18 BHN. :grin:

I look at hardness as a performance enhancer up to a point if I need top power. But " over " hardness is the great cover up for things we do .... wrong. Hardness is a correcting factor for guessing wrong on bullet design, lube choice, and powder selection.

If you aren't doing anything wrong, then maybe you are too hard and haven't found the right size or powder choice for the bullet you are using yet? Too many unknowns at this point to help much.

[joeb33050]

I bought some new linotype and cast some Lyman 31141s. The next day I couldn't size them down from ~.313" max to .309 where they needed to be-even with intermediate .312", .311" then .309" dies in the 450. They just wouldn't size without WAY too much pressure on the handle.
I was considering the Lee sizer. ~2 weeks later, after sizing 31141's in a softer = lead added lino, I tried the HARD 31141s again and they sized fine in one step to .309".
The bullets got a lot softer in 2 weeks.
This is the only problem I've had with hard bullets.
Al Capozzi cast bullets from Foundry type for years, they clinked when shaken. HARD!!! He shot them in a Stevens 44 1/2 32-40, also 308 Win, a lot, with no problems.
joe b.

[Char-Gar]

I will just make one comment re this thread. When talking about bullet hardness, we should always remember to keep rifle bullets and sixgun bullets in different pockets. To cite experience from rifle bullets as proof of something in sixgun bullets is not a straight apples and apples comparison. Some notions/concepts/principals about cast bullets are the same with rifle and sixgun bullets, but some are not.

[S.R.Custom]

I look at hardness as a performance enhancer up to a point if I need top power. But " over " hardness is the great cover up for things we do .... wrong.... Too many unknowns at this point to help much.

This was an ACP moon-clip gun that was converted... so it has the ACP rifling. :???:

That said, loads are warm --RCBS 250-K over 11 grs of Herco, yielding ~ 1000fps-- and if I had to guess, I'd say pressure is in the neighborhood of 20K psi. I've gone through all the regular gyrations with respect to powder choice, etc, and the Herco gave the best accuracy at this power level.

The problem is, when you get up to this power level, the bullets start to wander. At 25 yards, 3 or 4 out of the six you can cover with a quarter, and the other 2 or 3 will be sprayed 4 or 5" away. The phenomenon is not chamber specific, and gets exponentially worse with even just the smallest bit of lead streaking. I suspect bullet skidding on the ACP rifling, and was going to experiment with a harder bullet to test that hypothesis.

Sizing was mentioned as a possible difficulty were I to toss in "a bunch of tin," and I can appreciate that. Does it ever reach a point where the bullet gets too brittle? And what are the issues that arise from that?

[felix]

Tin will not make a boolit brittle, only antimony/bismuth will. However, too much tin will streak the barrel like leading when the amount of antimony is too low. Add only the minimum amount of tin, just enough to cover the amount of "unknown" antimony/bismuth. Say 2 percent? ... felix

[jhalcott]

I don't have a 45ACP revolver ,but I am under the impression the bore is a couple thousandths SMALLER than the 45colt. Since you said that it was "converted" could it be possible that there is a BIG difference in the chambers.? I have shot some VERY hard foundry type metals. Some time I'd get terrible leading, some times not. If you are looking for accuracy,this is most likely NOT the way to go.

[Trapshooter]

I don't know how well your mold was "running" when your boolits were cast, but one problem with quenching from the mold is the variable temperature of the metal when it hits the water. If the mold is a little sticky, or the cadence is not exactly the same, you will get a bit of hardness variation, that is tough to sort out, short of testing each boolit for hardness. Joe Brennan and friends did a test of this and the results were posted on the board here not too long ago.

It seems like I always have "problems" with something when casting, so I don't even try to water drop, I use an oven, and get pretty consistent results within a batch of boolits. If I water dropped them, I am certain they would be all over the map.

If you have time to fool with it, you could shoot single chamber groups to eliminate (or prove) a problem with chamber dimensions.

Trapshooter

[S.R.Custom]

Groove diameter is .452", chamber throats are .453", bullets are as-cast (or close to it) at .454". The "spraying" starts to occur at 900-950 fps, and the fact that 3 or four of them are still so tight indicates to me that the accuracy is "in there" somewhere. As mentioned previously, the phenomenon is not chamber specific.

Trapshooter: Good point. That could very well be an indication of variable bullet hardness, and would explain a lot. Which makes me think even more that a harder recipe would bring the hardness of the softest bullets to a higher minimum hardness. (Since I don't have the facilities to oven treat bullets --I'm not using my food preparation equipment to make bullets-- I have to manipulate hardness at the melting pot & quenching bucket as best I can.)

[beagle]

Joe...I got hold of some babbitt rich alloy off a railroad guy one time and made up a big batch of 429360s for my .44 Magnum. I was using a Lyman #45 at the time and they were just too hard to size. I'd have probably broken it if I persisted. Finally, I cut the mixture with some "pure" and they did all right but I had to recycle that entire lot of bullets./beagle


I bought some new linotype and cast some Lyman 31141s. The next day I couldn't size them down from ~.313" max to .309 where they needed to be-even with intermediate .312", .311" then .309" dies in the 450. They just wouldn't size without WAY too much pressure on the handle.
I was considering the Lee sizer. ~2 weeks later, after sizing 31141's in a softer = lead added lino, I tried the HARD 31141s again and they sized fine in one step to .309".
The bullets got a lot softer in 2 weeks.
This is the only problem I've had with hard bullets.
Al Capozzi cast bullets from Foundry type for years, they clinked when shaken. HARD!!! He shot them in a Stevens 44 1/2 32-40, also 308 Win, a lot, with no problems.
joe b.

[Trapshooter]

Absolutely right on not using food prep equipment for heat treating.

I spent about $20 on a cheap toaster oven, made some sheet metal baffles to try to keep the temperature even inside, and went to town.

I suspect your approach of casting hotter might help if the issue is with minimum hardness. If the problem is hardness variation, it might not help. Good Luck!

Trapshooter

[Bass Ackward]

This was an ACP moon-clip gun that was converted... so it has the ACP rifling. :???:

That said, loads are warm --RCBS 250-K over 11 grs of Herco, yielding ~ 1000fps-- and if I had to guess, I'd say pressure is in the neighborhood of 20K psi.

The problem is, when you get up to this power level, the bullets start to wander. At 25 yards, 3 or 4 out of the six you can cover with a quarter, and the other 2 or 3 will be sprayed 4 or 5" away. I suspect bullet skidding on the ACP rifling, and was going to experiment with a harder bullet to test that hypothesis.


SM,

Real good guess. Quickload says 20,500 psi at a standard OAL and @ 1000 fps out of a 4" barrel.

If I had to lay money on how to correct it, I would say it's sizing and not hardness.

While going over throat size is good to burn the slow powders, it never worked real well with the faster stuff. I use this trick to burn RL7 in a 44 Mag. That is not to say that I don't get better overall accuracy, but when the wild stuff starts showing up, I size smaller or go to a slower powder.

Now why? My guess is that the problem comes from internal voids in the bullets that you don't see. The pressure knocks the bases out of square and the muzzle pressure kicks them to the side, which may be why the others shoot. In rifles, some people confuse this with lube fliers.

But if you size smaller, you are in effect strengthening the base by lessening the pressure on it. Almost the same as going to a harder bullet or a slower powder. If you size to bore, you may need another 1/2 to a grain to get the same velocity and accuracy.

My guess anyway.

[xr650]

Lots of good info in this thread.
The more I learn, I find out how little I know.

[runfiverun]

i have heard of guys having to shoot a fairly hard boolit in their acp's to get good
accuracy
but i think they did it withboolit mix not quenching
you may be getting different hardneses due to quench
you may be blowing some of your lube off at the cylinder gap and throwing the
boolit a bit off balance
or that keith nose may be hittind the forcing cone off kilter

i think i would try a different boolit style before i did anything else maybe your 230 rn
or a 200 swc?

[Bass Ackward]

One more thing I missed. RCBS 250 KT.

While this is a beautiful bullet for a lot of things, Shooting it over throat diameter is not one of them. The sharp shoulder is basically easy to deform. It is very likely some of your bullets are hanging up enough in the throats when they get started that this deforms and you enter canted, thus throwing the base out of square. Especially in a new gun where these ramps still have the circular tool marks from the chambering process.

If you want to shoot over throat diameter, it is best to use an olgival design. And one that very closely matches the taper at the end of the case leading into the throat for a guide. Then as the pressure comes up and the bullet begins to move forward, the round will center itself in the chamber and this point and the recoil shield at the back of the frame so that it will enter straight.

You may see leading in this area as a result. But it doesn't have to be much to do this and it can be being blown clear so that what I am telling you can't be seen. Same with forcing cones. Keith Type or semis do better in well aligned guns and olgivals tend to do better if that bullet has to force alignment and survive impact. Only difference here is impact velocity.