Homemade built to fit Sig Sauer 516, barrel nut wrench. Fits perfectly. Here is a link to buy one of our wrenches.
Sig Sauer 516 Review with Problems and Issues with Shooting:
FTF, Cycling and Locking Open, Fixed, Solved with Buffer Spring
I have two Sig Sauer 516 rifles. Both had the similar problems that are posted all over the web about not firing correctly with not feeding in the new rounds (FTF)...