I ordered a set of Talley lightweight mounts for my x7 .243 made in ky. I was told that a Winchester model 70 is the same and that is what Talley sent me. After installing the mounts the rear did not fit correctly the curvature on the mounts only allowed the very edges to touch the rifle. I then took it to my local gun shop and they confirmed the rear mount was slightly higher than the front and it was not correct. After two weeks of back-and-forth with tally they cannot give me a good answer why the fit is so bad. My question is could the original X7 be any different than the XS7 or maybe some of the later ones they made and that’s the reason this amount is not fitting correctly. If there’s anyway to post pictures on the site I can do so to give you guys a better idea
The receivers did not change JM to REP production. I don't know anything about Talley mounts. The top of the receiver on X7s where the rear base mounts is not round in profile like where the front base mounts. For the rear base you need one that has the same bottom profile as a Weaver # 47.