Quote Originally Posted by 10/10 View Post
where can i get an slip on adapter to fit my 99 without damaging front sight grooves
I don't think there is one other than the HW push on silencer/moderator.

You could get a set of needle files and cut grooves in the adaptor as has been stated on this thread or file the barrel.

As far as I know it's the only ways to do it. Or tap it on like dayglowfroggy and hope it lines up right with no clipping of the pellets inside the silencer/moderator.