I have put a lot of rounds through my M&P 15-22 and I have changed the muzzle device a few times. All the shooting and tinkering added up to a slightly loose barrel nut. I noticed that accuracy was degrading a bit and my zero had wondered. I knew that a loosening barrel nut was a possibility so that is the first thing I checked when troubleshooting and once I established that as the issue, I went to Tacticool22.com to purchase a barrel nut wrench.
Consider this a mini review. The service is great from Tacticool22 and the products are solid. The wrench was in hand 3 days after I ordered. It is a piece of thick aluminum tubing with teeth machined on one side and wrench flats on the other. You just slip it down over the barrel so the toothed end engages the barrel nut and use a wrench on the flats to tighten (or loosen). There is enough clearance inside the tube to pass over muzzle devices that don’t stray too far from normal dimensions.
It took surprisingly little movement to tighten the nut. It was barely loose but had a noticeable effect on performance. I suspect many people with M&P 15-22s have borderline loose barrel nuts and don’t even know it. If you own an M&P 15-22, I highly suggest that you invest in the barrel wrench because you will need it sooner or later. My only regret is that I didn’t order the barrel vise jaws that Tacticool22 offers at the same time as the wrench.