I agree. AAC's cans are good. 'good' being the operative word.
You can use any .30 cal can out there. I would use SWR's .30 can. Its going to be the quietest one out there. (ANY .308 can will work).
If you've never shot a suppressed rifle caliber before, you're going to be VERY disapointed in the performance unless you're shooting subsonics (with sub's the AK isn't going to cycle reliably). On a M4 a VERY good can will make the 5.56/.223 report that of an unsuppressed .22LR. A silenced .30 cal (7.62x39 - AK or 7.62x51 - 308 - same bullet, different powder loads) will sound like a .22LR but with the additional sound of someone throwing a thick phone book on a hard surface (plus the deeper echo).
Either way, you're ears are still going to ring, people will still know what the sound was, and you're still going to be disapointed expecting more of what you see in the movies. The ONLY thing a suppressor does on a long-gun is to help hide the shooters location.