i put one of these on my scar17. caught the last hour of range time after work and of course i was in a hurry to get out there so i forgot all my mags. had to single load. the wife is still laughing about a single shot scar17. anyway, WHAT a DIFFERENCE this thing is over the pws brake!!!! recoil was really reduced and percieved back blast and concussion effect was about on par with a flash hider. im realllly impressed with this device. i installed using the supplied crush washer seems to be fine. heading out again tomorrow WITH magazines. if your looking for a great 762 muzzle device this may be the ticket. im liking it so far with just limited range time.