There's not enough information to give an exact answer, without knowing the type of 10/22 firearms you're trying to equip a scope. Furthermore, Primary Arms offers two scopes w/ the ACSS 22LR: 1-6x24SFP LPVO & 6x32 Fixed.
The eye lens diameter on the 1-6x24 is larger than the objective lens at 33.2mm, rounding up the length of the diameter is 11mm.
The objective lens on the 6x32 is the largest lens at 32mm = 10mm.
So you'll need a scope mount that at minimum clears either of these distances.