The GC vs. PB debate has been exercised in cast bullet circles for a loooong time. I'm not getting into this one. Frankly, for cast bullet handgun shooting I don't shoot magnum cartridges, never have to speak of and never will (I don't like being smacked around with each pull of the trigger) so I can't speak to that from personal experience now anyway. For me .32 Longs, .38 Spl, .45 ACP and Colt, and a few 9mm's now and then are it - and PB bullets satisfy me completely.
I can speak to their use in rifles though, ad nauseum. An inveterate innovator/experimenter with schuetzen rifles named Charlie Dell conducted lengthy experiments with .32-40 bullets a generation ago and came to the conclusion that the sand blasted bases of PB bullets (viewed on bullets he captured in snow banks) had a detrimental effect on accuracy, "sandblasting" caused by impact of unburned powder kernels before they were ignited*. Further testing on bullets that purposely didn't fit the bore showed distinct signs of "gas cutting"- streaks of melting along the rifling engraving on the bullets - and coincidentally the bores in which they were fired in were gobbed up with lead (when they never exhibited leading before). Subsequent construction of identical bullets but with GC's (from a mold made with the same cherry, but altered to create a GC shank) yielded better accuracy and zero leading with no signs of gas cutting in the rifling engraving. Conclusion: since the bullet base is the steering end of a rifle bullet, any time you screw with it in any way you're going to mess up accuracy (a moot point maybe when it comes to putting a magazine full of pistol rounds into a silhouette target at 10 yards). (And golly, Dr. Mann proved that conclusively 110 years ago - yet we insist on re-inventing the wheel every generation.)
It's no secret that GC rifle bullets sans GC's deliver excellent service at low velocity, but fall on their faces if velocity is stepped up and GC's are still absent - the various effects of powder spanking them. And oh my, try shooting a PB bullet (or a GC bullet without a GC) at 2000 fps some time - and get back to me. Powder coating may well (probably will) ameliorate that, but someone else is gonna have to tell me about it.
*His assistant in those experiments is still with us and described in detail the course of those tests to me over beers and a campfire a couple years ago after a match. Those results parallel pretty closely my own experiences/observations, with target rifles and cast bullets, not, like I said with pistol bullets though. (It's why I insert a wax wad in the .32-40 case mouth before inserting it into the chamber behind a previously breech seated bullet.) With pistols as long as I can hit our little steel targets on my buddy's plinking range and I don't have to scrub lead out of the barrel later, I'm good to go (and strict attention to bullet fit and alloy creation takes care of that, the actual target hitting or not hitting is on me). But, I can't help but believe a lot of the lessons from rifle shooting apply to pistols too - I just don't care enough to find out comprehensibly because of my aforementioned pistol needs.
