I know 8.2 works good on the fal i would suggest something like 7.20 or 7.40 something in that area. The smr sboots slower and at 8.20 i can see it getting skippy on the smr but what u want in a rapidfire is sometbinv that shoots the fastest at the lowest possible speed settings. I think if u work your sps up from 7.0 u will find a good sps somewhere around 7.20 between 7.40. That would be my guess.