I’ve been looking into all-copper revolver bullets with particular focus on the 44 Magnum and 45 Colt.
In rifle bullets, the rule of thumb is that when you go from a lead-core bullet to a monometal design, you can drop one or two weight classes and get similar or slightly better performance. In .308” diameter that’s a drop from 180 grains to 150-165 grains and some guys are willing to drop down to 130 grains. The caveats are that monos need speed to expand, and that they’re best when they hit bone—lung shots don’t always offer enough resistance to make them open unless impact velocity is really high.
The closest thing that I’ve seen to a similar rule of thumb for revolver bullets is that a monometal bullet SEEMS to perform about like a cast bullet that’s 30% heavier. I haven’t been able to find any trends in how much velocity these bullets need to work properly.
I immediately looked to see what @
DocGKR has to say about it, and found this:
https://pistol-forum.com/showthread....-Purpose-Loads
In an update, he adds
Velocity of this load was 1,308 fps and penetration figures SEEM similar, which SEEMS to uphold the “+30%” rule.
Barnes loads a 225-grain XPB in the 44 Magnum at 1,145 fps. If the “+30%” rule holds true, then that should penetrate about like a 292-grain 0.429” bullet, and would roughly match the old Federal CastCore 44 Magnum load but with significantly less recoil. Federal also loads the 225 Grain XPB Hollow Point to 1,280 fps and Remington offers it in their Hog Hammer load at 1,235 fps. I couldn't find velocity figures for the Hornady load in question.
In the 45 Colt, Barnes loads a 200-grain XPB at 1,025 fps. I haven't chronographed it yet, but recoil is mild in a New Model Blackhawk with a 5˝” barrel--about like an old-school 38 Special 158-grain RN load in a Smith & Wesson N-frame. If the “+30%” rule solds true, then this bullet should work about like a 260-grain cast bullet. Velocity is mild in deference to the Colt Single Action Army, but 260-grain .45-caliber slugs at 1k fps have been counting coup pretty decisively since 1873 so it's no slouch.
I pinged the dentist himself about this, but I haven’t heard back from him yet.
Okie John