How Hard Do 125gr .358" Cast RNFP Slugs Need To Be at 875 fps Cowboy Action?

With bullet prices going up, and me with tons of lead and all the molds and equipment I need, it's time to get to casting again.

Between my wife and me, for Cowboy Action, we shoot 150 .357 RNFP rounds per event, plus practice, in my .357 Vaqueros and 1873 Winchester lever action. (She shoots .32 H&R Mag in her pistols. Not presently casting for those.)

I load the .357 rounds at the Hodgdon minimum of 3.5 grains of Trail Boss, which they say pushes the slug at only 875 fps.

Plan to powder coat after casting.

Do I really need to harden much over pure lead? The powder coating should resist leading.

The Winchester originally shot pure lead, didn't it? And cowboys cast their own .44-40 slugs over the campfire. Not exactly scientific alloys, there.

In the past I alloyed one pound of wheelweights to three pounds of pure lead.

Do they even need to be that hard?

Thanks.

I'd have to go look it all up again, but it seems to me that Uncle Elmer & contemporaries pushed bullets toward 1000 f/s using 1:16, 1:20, and even 1:30 tin:lead alloys. On that basis, I cannot imagine that very much more in the mix (antimony, or maybe even a bit of arsenic) than some tin would be needed to drive bullets to 875 f/s without leading. If wheel weights containing arsenic are mixed in, a bit of heat-treating would be decent insurance.

Dead soft, pure lead with no powder coating would be fine with a soft lube. Bullet does need to be over groove diameter with cylinder throats also over groove diameter and bullets need to not be swaged down by seating is cases with small mouths. Fit is most important. You can't fix bad fit with hard lead.

Tim

If your concern is about leading then properly applied powder coat or HiTek should prevent that with lead of just about any hardness (I recall Ausglock reporting in the monster HiTek thread that he coated dead soft lead for 45 ACP [sorry, I don’t recall his velocity] without leading).

I’m not as sure how hardness might affect accuracy, though at my range’s SASS club, shots are under 25 yards, and most are much less, with very generous targets, so maybe that’s not a big problem.

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Originally Posted by kevin c

... at my range’s SASS club, shots are under 25 yards, and most are much less, with very generous targets, so maybe that’s not a big problem.

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Ain't that the truth! More like 7 yards, with 12"x16" targets.

Shot 20,914 of the Lee 125 RF at Cowboy matches and practice. 357 case, same load of TB, SP and topped with at bullet lubed and sized.

Shot 29 cleaned matches including the Florida state match, but Big and Close does get old, so I moved on.

Check Missouri Bullets of you don't want to cast their HI-TEK bullets are great to use.


Casted the bullets between 9 and 12 BN; That's what I use for all my revolvers.

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Originally Posted by Liberty1776

With bullet prices going up, and me with tons of lead and all the molds and equipment I need, it's time to get to casting again.

Between my wife and me, for Cowboy Action, we shoot 150 .357 RNFP rounds per event, plus practice, in my .357 Vaqueros and 1873 Winchester lever action. (She shoots .32 H&R Mag in her pistols. Not presently casting for those.)

I load the .357 rounds at the Hodgdon minimum of 3.5 grains of Trail Boss, which they say pushes the slug at only 875 fps.

Plan to powder coat after casting.

Do I really need to harden much over pure lead? The powder coating should resist leading.

The Winchester originally shot pure lead, didn't it? And cowboys cast their own .44-40 slugs over the campfire. Not exactly scientific alloys, there.

In the past I alloyed one pound of wheelweights to three pounds of pure lead.

Do they even need to be that hard?

Thanks.

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I thought that cowboy action prohibited polymer coated bullets?

at 900fps you could pan lube with alox.

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Originally Posted by Shanghai Jack

I thought that cowboy action prohibited polymer coated bullets?

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Polymer coatings are allowed. No jackets or gas checks allowed, however.

From Jan 2023 Cowboy Action Handbook:

REVOLVER AND RIFLE AMMUNITION
- May not be jacketed, semi-jacketed, hollow point, plated, or gas checked. It must
be all lead. Moly-Disulfide, polymer coated bullets, or equivalents are acceptable.
- Must be of “single projectile” design

What I like about polymer coating is its cleanliness in handling.

Tried powder coated pure just to see if it would work for some light 38 special loads. 90% shot fine in one gun, but wouldn’t shoot at all in another. Leading wasn’t a problem, but I think the case tension was squeezing down the boolits and making them undersized. A larger expander might have helped, but I just went to 50/50 pure/clip on wheel weights and all was well.

Are you using “Cowboy” dies? I think they may have a larger expander.

Going closer to pure lead will shrink your bullets some, and odds are your mold was cut with something like wheelweight or Lyman #2 in mind. You'll want to check diameter if you start going softer - hardness is not the key preventer of leading at your speeds; correct bullet fit is. Your powder coat will probably bulk them up some - not my area of expertise.

I'd also want to make sure my bullet noses didn't turn to putty while feeding through a lever gun.