The factory aluminum clamp on rings are soft and allowed the scope to slide through them and also, the aluminum allen head screws that tighten to the base stripped out the heads. I found a set of Weaver #61 flat bottom bases that are suppose to work but, the screws feel like they might be too big in diameter when I tested one without the base. The holes seem to line up on the receiver just fine though. I read on another forum where a person ordered a set of the Talley rings and found the same problem they sent him two more sets of screws to try but, same thing. He said finally, he put quite a bit more force on the screws and they went in just fine? Are the factory filler screws plastic maybe a little undersize and I too, need to apply more force? I just don't want to bugger up the threads in the receiver where I can't use it any more. The factory plugs measure 3.0mm. but I can't hardly see or feel any threads on them. the Weaver screws measure 3.4mm. in diameter and the threads can be seen and felt easily. I'd sure appreciate some info if possible, Thanks!