Thread: Using a suppressor with a larger diameter than the rifle caliber

Got told by Bert at ODL that my 7.62 can would still suppress a 5.56 very well (though not quite as well as a 556 can would) so I think you will be fine.

I suspect it is because the 7.62 can has a bigger internal volume than a 556 can which somewhat makes up for the hole size difference.