I have something to say here. I bought a used 412 and new mounts, new Lothar Walther barrels fitted in 9.3X74. My problem is actually quite simple. When the QD mount is applied the locking collar strikes the bottom of the mount just before fully coming into battery. I am going to grind (mill) the bottom of the mount slightly to solve the problem. I wanted folks to know the dealer went to the manufacturer's representative just to get their take on the problem. Remember they would have some legal problems if the rifle fired out of battery with the ensuing damages. The dealer forwarded directly by email the manufacturor's comments. I wanted folks to know the results of my contacts and after sale assistance from the dealer. Russ Gould of Oregon is the dealer. No, he hasn't offered me anything or even asked for my advertising on this matter. I feel things got out of hand previously and the positive should be known in this public forum. Take care and God Bless. Packrattusnongratus