The concept apparently is sound. I'm surprised more companies don't offer something similar, especially now that oogly stuff hanging on the end of the barrel is pretty widely accepted. A range buddy bought a couple of those rubber dinguses for his .22s and reports substantial improvements, though he has to fiddle with them when he changes ammo types, or even lots in some cases.
Ruger put a similar weight on its discontinued Target Mini 14, and according to reviews it worked too.
Are the Boss rifles still available, or just used ones?
