Home Forums Hunting & Shooting Handguns Max Vel in the 357 Magnum with Cast Bullets

What max vel would you recommend in the 357 Magnum with a Gas Checked 158 gr SWC-HP with a BHN of 5 ?

BHN 5 is pretty soft bullet, even with a gas check I suspect you'll see leading above 1000fps.

Very soft

That does soft to be running over a grand.

Thinking of trying CFE Pistol 6.5 gr's around 1000 fps maybe a little more or a little less.

It's odd to have a gas check on such a soft bullet.

The bullet is Rim Rock 158 gr SWC-HP with Gas Check I have 500 of these bullets

https://rimrockbullets.com/xcart/g-ch-38-357-158-gr-swc-hp-per-100-in-a-plastic-ammo-box.html

I don't have experience with that particular bullet, but I doubt it is 5 BHN, that would be close to pure lead.

You can call Rim Rock and ask them about the hardness, but if made from a standard alloy it should be ok up to 1200fps.

It looks like a good bullet.

I thought pure lead was 8 BHN.

That's got to be a typo.

You thought wrong and it's not a typo.

5 I believe.

They probably used very soft alloy for that bullet thinking it was necessary for hollow point expansion, but if the hollow point design is any good, 5 bhn is way too soft for best performance at anything above ~800 fps. At that speed, you don't need a gas check, so the whole thing looks like a real mismatch to me. If they were ~10 bhn you could push them to max pressure in the 357 and have a good performing hollow point too.

rimrock emailed me and said 1200 max

Think about BPCR and muzzle-loader bullets. Most solid bullets (not sabot) and round balls are pure lead in muzzle-loaders and some guys shoot pure lead in their BPCR, only adding just enough tin to allow complete mould fill-out. BHN on the lead-tin alloys (30:1 alloy) is very low.

These guns don't really lead (my Sharps doesn't lead at all) or badly deform the bullets upon firing and their velocities are ~ 1,000-1,200 fps.

Ed

Ed, I think you misunderstood my post. I didn't say the bullet couldn't be pushed faster than 800 fps, I said it's too soft for the hollow point to work well above that. Black powder solid bullet stuff doesn't have anything to do with that.

At 1200fps I'd expect the front half to completely shed off right now and you'd end up with a lighter weight wadcutter.

I'm also with Yondering, it would be fine at 38 special velocities.

Yes, exactly. I've experimented a lot with cast hollow points, and that is what pure lead hollow points generally do at higher velocity. Often the front half doesn't even fragment, but shears off as a donut which is pretty useless; at least a fragmenting hollow point does a good bit of damage.

That's an interesting point, but the internal pressures and temperatures are much lower for black powder, so there is not a direct comparison between the two. The alloy hardness requirement is lower for BP.

But getting back to the BHN of those bullets, if you can scratch them easily with your fingernail then they are pure lead, if not, then they they are an alloy with a higher hardness rating...as I suspect they are. It wouldn't make much sense to cast those bullets dead soft when a moderate alloy would perform better over a wider velocity range.

A pure lead bullet has very effective terminal effects, but manufacturers that provide them do so specifically for BP guns or low velocity rounds.

Rim Rock does specifically state 5 BHN for those bullets, while they sell others at 10-12 BHN, so I don't see any reason to question the hardness values, just the logic in doing it that way.

A 10bhn hollowpoint would be a good place to be

The only reason for a 5 bhn hollowpoint is 700-800 fps muzzle velocity. So it's a bullet designed for a snubby 38 sp. As a very crude ballpark rule of thumb for cast hp's, multiply the bhn by 100 to figure out what velocity they will need to expand.

Yep.

It also depends on caliber and how flat the face is to begin with.

since i have a couple of pounds of Unique i will try 6.0 gr with this bullet in my 686 4 inch and GP100 in 6 inch if it leads i will then use 38 SPL brass

I have to disagree; that "method" is so crude that's it's meaningless, and not a method at all since it doesn't work. Size and shape of the hollow point cavity is far more meaningful than hardness values for determining expansion. You can easily have a 5 bhn hollow point that won't expand at 1200 fps, or a 10 bhn hollow point that will expand at 600 fps. I've done both. Another example is the solid copper Barnes hollow points - the 45 cal version I tested (200gr IIRC?) expanded at 700 fps, and is far harder than even hard cast lead.