Colt did have a flash hider early on, IIRC it was on the 11.5in XM177 and it did offer some DB reduction.
But like rob_s said above, OPS has been offering the M4-S for a good while now...I think over a year, if not two. It goes for $215. You can put an M4-S on any size barrel.
The Surefires are meant for 14.5 and beyond and some places are saying they bring sound down at the ear to 141db. I think 141db is still on the verge "ouch" levels.
I'll agree that the pictures where informative. Thats why I linked it. But that dude was too funny. When I saw him holding up the 12th to the mini can, I couldn't help but laugh. It seemed like he thought that was the ONLY can OPS makes.
I hope to see more companies producing smaller cans...I like the concept!

