You need a vice to hold barrel or the barrel will move, iI tried it to be cheap install the shroud & every other shoot was a FTF, went to Wendy's got a frosty & start thinking.
First I cleaned the bolt will goback but not completly go forward & the bullet will not go in all the way.
Ok put the A1 flash hider back in & tighten it the barrel moved a slight. Put in mag shoot whole mag rapid without problem
Took the A1 back out but this time very careful , put in the shroud from Keneti-tech now no problem. For beeing cheap it almost cost me. As I know warranty won't cover custumer stupidity .