I put one on a 1920's G model .300 Savage. At screwed all the way down it still shot 7" high at 100 yds. Disassembled it to see if I could fix it, couldn't put it back together. Sent it back to Marbles, they reassembled it, and I assume put a shorter post in it, and now it's perfect. Sometimes being a dumbass pays off. I know this doesn't answer your question but it may provide a different solution to the problem.