Not ideal but it will still largely work, probably. Obviously the smaller it can be the better, but depending on the baffles it will still be 85-97% as effective as the smaller diameter opening is my estimate (I do only Donnyfl so hard for me to say with that brand).
PLUS SIZING A SILENCER IS COMMON PRACTICE WITH THE DONNY FL, BRAND , ( WHAT I HAVE ) WOULD HOLD TRUE WITH OTHER BRANDS AS WELL , I WOULD CONTACT THE PARTICULAR BRAND ODB, AND ASK THEM. WHAT THEY RECOMMEND .