I actually had the same problem with my first .450. I sent it back to Marlin and it was solid. I am sure the .375 recoils a little less though!
"The only purpose for a pistol is to fight your way back to the rifle you never should have laid down."
"I won't be wronged, I won't be insulted, and I won't be laid a hand on. I don't do these things to other people and I expect the same from them." -John Wayne