I also posted this in the Weatherby forum:
I have a Weatherby Mark V Accumark. .338-378 and it has some recoil. First I put a cheap Bushnell on it just to work up a load. Worked up a good load that would have all shots touching at 100 yards. Then I bought a Night Force scope. Mounted it and went to the range. On the third shot the scope base screws sheared and the scope went flying. Luckily, I reached up and grabbed it before it hit the rocks. Had to drill out the screws and retap the holes with larger screws. Remounted using Warne mounts. First few shots were fine then they went to scattering all over the target. Tweeked the load then they went off the paper all togeather at 100 yards. Moved back to 25 and started over. Got to 100 again then off the paper again. Checked the bases, and rings, everything is tight. No movement can be detected in the scope. I'm sending it back to Night Force.
Picked up a Pentax at a going out of business sale two weeks ago. So on a whim mounted it on the Weatherby. Went back to my original load and went to the range. Looked through the bore and aligned the scope and bore at 50 yards. First shot was 6 inches low and 4 inches right. Made corrections and moved to 100 yards. Second shot was 4 inches high dead on center line. Made corrections, and next three shots were in the bullseye, all touching. Moved to 200 yards, using the ballistic marks on the scope, shots were two inches high. Moved to 300 yards, again using the ballictic marks, again shot was two inches high, with a two inch group. I'm Happy!!!!! Taking it Moose and Bear hunting Friday.
Went to the gunsmiths shop yesterday after leaving the range to discuss my scope problem with him. He said he has seen two Night Forces scopes shaken apart by the 378 Weatherby derivatives, and three Shepards scopes also ruined by them. I asked about the Pentax, he said it should hold up. We'll see
