Re: 5.56 can for 8" sbr?
Depends on what is intended with Full Auto fire.
Belt fed?
10 continuous 30 Round Magazines?
1 or 2 30 Round Magazines?
A lot of the cans out there will handle some level of full auto fire. If you are torching your gas tube and barrel, then you probably are going to destroy your suppressor. If you are judicious about how you are heating up your rifle and suppressor, then you will be fine.