I agree with CZ, "if you shoot them----it's gotta be repaired." I pound about 4500+ rounds a year through my NIDs I have had a few barrel lugs come loose. My recent failure was a 1927 NID that I had been shooting 35 years. It is at the gunsmith currently being repaired for another 80+ years. I had my heart plumbing "fixed" about 12 years ago. My NIDs and my heart are all repaired and we keep on doing what we were made to do.

Walter c. Snyder