I made a faux HEL E4A shroud for my M16A1, was wondering if there was anything similar used on the A2.

I've seen the KAC NT4 on the A2 and the A4.

Ops Inc (of SPR suppressor fame) made/makes the "3rd model" which is the old 727 carbine suppressor.

I read somewhere here that Ops Inc was out of business, but there was another company that had picked up their designs and was producing them... I've been meaning to look into it myself, just out of curiosity. Ops Inc was good stuff.

ETA: I looked into it, and ALLEN ENGINEERING was the actual producer for Ops - a very interesting read if you Google it, so I won't go into it, but he is still producing them.