I purchased my 91/30 and the previous owner had installed the ATI rail and bent bolt. I initially went with a Sportsman Bushnell.. (trash) then found a better scope at Wally World. Once I corked the barrel, and spent weeks cleaning the barrel, I started creating cloverleaf holes at 100 yards. At this point I stopped the J&B red rouge barrel cleaning. I've put hundreds of rounds down range since that point, and the scope holds zero perfectly. I did make one minor modification... right near the back of the ATI rail, there was an opening the size or thickness of a piece of paper. I took some black thread, moistened the thread and smeared baking soda on it. Then I wrapped it round and round for about 10 turns. A drop of CaynoAcrylite (CA - Zap or crazy glue) glue turned the thread into rock and it bonded to the rail and the receiver. Before doing this each shot would produce a "Twang" as the short end of the rail vibrated. With the Thread/rock in place the sound disappeared.
Love my MN...
KKKKFL