If your gun has 1:12 twist bbl,remember that the solid copper bullets are somewhat longer than the same weight bullet that has lead in it's makeup.
If bullet is of the "no lead" makeup,I would not use anything over a 50gr. If lead core a 55gr should be good/ok.
Remembering that back in the day when I carried a XM177E2 with it's 12 twist bbl . . . we tried to switch from the M193 to the M855 (55 to 62gr) and they would tumble (destabilize) after leaving the short bbls. --- SAWMAN