I'm sure the couple of decibel difference will not matter, mostly concerned about accuracy. I don't feel like it SHOULD matter, then again, don't know for sure...
I've gone so far as to shoot 22LR from a 50 cal diameter can that has an internal volume made for 45-70. Not as quiet as the proper baffle size, but it works fine and is much quieter than un'canned.
No accuracy or velocity issues with 30 cal lead from the same can.
I use my 308 AAC Cyclone on my AR-15 16" barrel and don't need hearing protection... (Unless under a covered firing point), and it's just fine on both my M700s 260 Rem. 26" barrel, and my M700 308 with the 24" barrel