Which bullet? Which barrel?
I get the beginnings of hairline smiles in a stock G20 at 7.8, but am OK below that w/ 220ish lead.
In a LW barrel, I start at 7.8 and work up, but 8.2(I think) is 36Kpsi under a 200g jacketed, so I assume that you are overpressure by 8.5 if not sooner. It won't show in the AM barrel as a smile, but it will loosen the primer pockets when you run them hot.
I don't know anything about the 220g plated bullets, or their pressures.
Last edited by Any Cal.; 06-16-2012 at 18:47..