Brinell hardness

[Hondo 60]

How does hardness affect application?

I know you can't drive soft lead too fast.
It would result in leading of the barrel.

But what about the other way around?
I have some .358" bullets from MBC "357 Action" - Brinell 18.
They're designed for 357 mag.

Can I use these in a .38 spl as well?

 

[Walkalong]

The hardness is needed for velocity so it can maintain a grip on the rifling without skidding. (going straight instead of following the twist of the rifling) If the bullet skids, it breaks the seal in the bore and leads due to hot gases leaking past the bullets base causing gas cutting.

You can get away with more hardness than needed if it seals the bore really well. If it seals well enough without needing the pressure to bump it up, it usually won't lead. (Easier to do in autos vs revolvers)

The low .38 Spl pressure is not going to "bump up" those 18 BHN bullets to seal the throats and bore so they must be big enough to start. You may be fine, and you may not. Depends on the bullets fit in the throats.

Ideally, you want a softer bullet for .38 Spl.

 

[LiveLife]

And that's why Missouri Bullets offer softer 12 BHN bullets.

 

[Hondo 60]

I currently do have MBCs Cowboy 11 which has a BHN of 12.
But every now & then I run out.

Walkalong - you answered my question & I appreciate that very much.
Not only "no don't" but the why not! thank you!

 

[Jesse Heywood]

I have found that a quick tumble in alox or rooster jacket allows shooting Brad's 357 Action at 38 velocities without leading.

 

[Buck Snort]

I'm a big fan of gas checks. They seem to hold the leading to a minimun and aid accuracy as well.