Average db reduction from a 556 can is about 26-33 db from what I've found from various mfgs. Only 21-28 db average from 7.6 cans (with .30 cal rounds; Surefire would not list theirs). Since the amount of dbs reduced when shooting smaller caliber out of a larger can is less, then the sound reduction for the way you are advocating is generally less than 21-28 dbs. Those are all less effective then a dedicated 556 can. While none will get completely ear safe, every decibel counts. Today, my 10'5" SBR with Battlecomp 2.1 shot 148 db at the muzzle, 120 db with Gemtech Halo (using M855). Anything over 100 db is considered hazardous according to the CDC. That's a reduction of 23% compared to a 7.62 can at 16% (notional @ 21 db reduction). Additionally, if value is your concern, then a $1400 SureFire 7.62 suppressor is not within those lines when there are other viable 7.62 options at less than half the cost.
Considering the 2 way noise, there is a huge difference based upon my experience, even in a hallway, of having yourself suppressed and possibly others with you. Unless the other shooter is right on top of you, their noise is greatly reduced anyways.
I don't have any interest in this discussion as I'm not sales for anything other than I see too many people, who aren't shooters, advocate bigger can for no reason other than their friends said so. I don't know you and I'm not implying anything here. Only providing facts and lessons I've learned the hard way.
