Great thread, btw, guys!
I'd have to agree with dm and shadow... "The only options that remain are, shorten the cartridge, ream the barrel(s), or choose another bullet (in no specific order)." and "too little throat".
I, personally, had no toubles with LSWC or BTB in my stock length Barsto G20. Never had any issues with any of my other AM barrels, either, with WFN (Federal, Barsto, KKM, LW, Fusion). Guess I was just lucky! I do usually set my BTB's to about 1.24x.... maiinly because my Fusion mag doesn't like 1.26" btb loads... they jam up the mag.