Originally Posted by
jcren
Pc or lead won't make a significant difference in a 45 carbine @ 100 yards. I think, based on my experiences with the 45 acp carbine, that you are running into one of two problems. Either the heavy bullet is simply too long to stabilize at a given speed out to 100 yards, or your muzzle velocity is barely supersonic ( like 1300 or less) and the bullet is getting pummeled by trans sonic buffering about 70 yards out. Short, fat, flat nosed bullets don't do well trans sonic apparently. I'm my 45 acp carbine, I found that I either have to keep it around 1100 at the muzzle or kick it above 1300, preferably 1400. My 1250 ish loads would shoot lights out at 40 yards, decent at 60, but at 100 I was seeing 6-8 inch groups!