Is there a spec for these?  Such as heat treatment/temper and finish.  

I really want to put a YHM 5C1 Phantom on my 14.5", and since it will be permanent, want to choose the right one the first time.  I was a little surprised when a YHM rep called me back in a follow up call and informed me that they use 4104 steel, and that they do not heat treat or temper, at least the 5C1, which I inquired about.  He also said they phosphate for finish and fixed all flats to be even, with a recent change.

Everyone around here seems to like them and have no issues.  I have a feeling that it will do just fine, and its price is not bad.  Maybe only the ones that are supposed to work with suppressors are hardened?

Do the other big flash hider manufacturers (A2, Smith, KAC QD, etc...) do theirs any different?