I found the "magic arm" to require adjustment too. Found some other brands that do not with my 6.5 CM. The 338LM does require a bit more attention. What brand is the recoil sensor? I would like to look into that..I tried the non barrel mount exactly like you have there, my rifles recoil too much and require constant repositioning of magic arm. Got a labradar with a recoil sensor, and I might miss 1/100 shots.