Guys, I'm always looking for an "edge" in competition shooting within the rules and sometimes outside the norms. I did some experimenting with PC in muzzleloaders and modern "stuff". I've also experimented with "water quenching".
Here's the facts.
PC in modern "stuff" is a great technique IF you want to push a cast bullet past it's inherent limits without leading. I'm pretty much convinced that leading in modern "stuff" from cast bullets is due to the different rifling depths and twist rates and attempts to push a bullet alloy past all reasonable expectations from the material. I'm also convinced that the PC process of heating may well be "tempering" the alloy to a degree so that helps.
Now for a traditional type of muzzleloader shooting real black powder. I ran an experiment PC several bullets for my PRB and Civil War guns. Any accuracy change? None. Any fouling change? None. Net result- Any benefit in traditional muzzleloading guns- None. Worth the effort in traditional muzzleloading? No, unless you're just a mad scientist masochist and then it's only self gratification with no benefit downrange. In a traditional muzzleloading gun, what the ODGs knew still holds. Get bullet design right, the alloy right, the powder charge right, the lube right, and the gun will shoot well.
As for modern stuff, it works to a degree but that's a discussion for another forum.
As for water quenching. All metals react to some degree from thermal cycling techniques. Exactly how they react is subject to the alloy in question. A quick water quench will result in a "hardening" of the bullets. I haven't tested if it remains hardened but lead changing hardness over time is a well documented fact. So water quenching with traditional muzzleloaders and Civil War guns. Any accuracy change? None in PRB, loss of accuracy in minie guns. Any change in fouling? None either way. Any change in conical accuracy? None with real black powder. Net conclusion- is it worth it in traditional muzzleloading or Civil War guns. No.
My conclusion, PC needs to be kept where it belongs, with modern "stuff" as there is no benefit to what the ODGs did with a traditional gun with real black powder.