Lead casting 357 what breinel hardness?

[dbur525]

I have a new model 92 357 stainless with 16 jnch barrel
I have bullet casting equipment and plenty of left over lead from when i was casting 45-70 bullets
The hardness i was casting is 23 breinel hardness.
What would be ideal for my rossi 357 ?
Im worried about leading the barrel.
My 45-70 i was casting 540 gr blunt pile driver bullets with gas checks at near max velocity around 1700 fps
I know the 357 runs about 2100fps just wondering if i need to mix up some harder lead fir the additional fps of the 357
Thank you David

[GasGuzzler]

I doubt you'll see 2100 from a .357. It's not FPS that leads it's pressure and fit. Get the proper bullet to cast and a gas check if you want to even approach 2100 and the hardness makes less difference to a point.

[Ohio3Wheels]

What Gas said, you need to slug the bore and find a bullet you like and aim for a thousand over groove diameter. If you're wanting to work toward 2100 fps I'd recommend a gas check. Lastly keep in mind it is possible to get the alloy too hard. If the bullet doesn't bump up to fit the bore and seal it you'll get leading.

Stay well, be safe, make smoke,

[severnsider]

Good day Gents. These queries/observations relate to my 20" Rossi in .38/.357.

On the matter of Brinell hardness, I've been using 125gr Truncated Cone which are advertised as 15.4 BHN, with a maximum pressure of 19,100psi. So, a couple of questions if I may?

(1) Is a Brinell no. of 15.4 considered to be "hard cast"?
(2) These shoot very well at around 1400fps using N320 in .357 brass. I don't detect any signs of excessive pressure (although Quickload and GRT suggest that the load I'm using will produce 21-24kpsi) so would anybody have an opinion on whether bullets of this hardness (no gas-check) sent at that speed would result in leading of the barrel?

I've researched about as far as I can on the internet and would appreciate some real-world views from you folks who are knowledgeable about material hardness and projectile velocities!

Many thanks!

[severnsider]

Doh! Typical....... I think I may have found the answer to my own question (Hunters Supply hard cast bullets) regarding the 125gr TC items:

A great bullet for competitive shooting or small and medium-sized game, these high-quality cast bullets are composed of 6% antimony, 2% tin and 92% lead with a Brinell hardness of 15. They are rated to 1600 fps without gas checks.

Just need to better understand the "max pressure 19,200psi" side of things now........

[GasGuzzler]

Pressure and fit are the considerations for a cast bullet. FPS is merely a result. I'm really don't know what "hard cast" means but I suspect most people would see leading from a non-GC bullet at the pressure required get to 1600 FPS.

[severnsider]

Pressure and fit are the considerations for a cast bullet. FPS is merely a result. I'm really don't know what "hard cast" means but I suspect most people would see leading from a non-GC bullet at the pressure required get to 1600 FPS.

Yes, thanks - I'm beginning to be less concerned about the velocity. Fit seems good to me (after examining recovered projectiles which have been sent out at <1000 fps) and I take your point about FPS being merely the result. I was under the impression that leading was likely to occur at velocities above around 1200fps, but the sources of that information have never indicated what hardness of bullet was involved, so really only part of the story.

The Rossi shoots very nicely with a lighter bullet; certainly better with a TC rather than a RN, and at MVs of between 1200 and 1400 fps. I just didn't want to risk leading if the advice was that those speeds were excessive for a good-fitting, non-GC bullet.

[Ohio3Wheels]

Wipe the bore and take a look with a fairly bright light. If you're getting leading you'll see it a streaks in the bore. I'm thinking that if those 125s are a decent fit you're probably okay. My '92 seems to prefer 358 to 359 depending on the amount of bearing surface.

I have the Lyman mold for the 125 truncated cone. Used a lot of them in the 9mm, but never tried them in the 357s. I may have to cast a few and give them a try.

Make smoke,

[severnsider]

Thanks O3W.
The bore is shiny and bright and I don't see any signs of leading. I have found that the truncated cones in both 125gr and 158gr (both sized at .358") work far better in my Rossi than the RNFP type.
I don't cast my own but I think these bullets are a little different in dimensions to the Lee type (based on measurements that I have made compared to the dimensions for the Lee given in "Quickload").
I have not yet tried the 140gr truncated cone, but I'm guessing there would be very little difference in performance.
The one thing that I have learned in the past couple of years is that the Rossi with its 1:30" twist really does seem to appreciate the lighter bullets being sent downrange at a good speed in excess of 1200fps.