I don't hit my nut wrench with a hammer! I made an in line action wrench so all i have to do is pull the bolt and then use the action wrench and tighten the nut just like you would any other nut, no impact required.

Removing a factory fit barrel the first time I use my clamp on action wrench and hit it with a 5lb. brass hammer while holding the nut wrench in a cheap drill press vise to keep things straight. One whack is all I've ever had to use so far.

Bob