The design faults of the Redfield style, windage adjustable bases became known to the tactical crowd during the vietnam war. The Remington varmit rifles the marines used wore Redfield 3-9X scopes on those mounts. Basically the same scopes alot of hunters use. Same size and weight.
While scope weight may contribute to this problem as well as recoil, the problems in Vietnam came from the rifles being knocked around. The problems I've seen with them, the scope breaking loose of the rear base, were the result of that treatment. E
interesting post E -- knew these mounts were the mount systems used there, but didn't know that there were some of the extreme issues going on that you say occurred there--though one could easily infer that there had to be zero shiftings due to knocks and bumps in that type of hard use setting.
most of us have used these mounts, and in almost every situation they leave much to be desired. yet folks have used them successfully in concentrated/hard use environments--but care must be taken. Mawhinney used them with great success in his day--though i'm sure he would have preferred having a rig with the mount systems commonly utilized today.
i've never had a set fail (with respect to breakage, not zero shift), but i'm very careful with my gear, and typically shoot rigs that are fairly light in recoil--with the bulk of them being .22 and .24 caliber. nevertheless, i don't care for these rings because even if you're careful with the rig--with respect to knocks and bumps--in the back of one's mind is always the idea that they will possibly move, thereby affecting zero. I have however, seen the lower recess on the ring post that engages the windage screw, almost completely sheared off in heavier recoiling rigs, as there is very little metal there. in one example i looked at where the rings had been completely removed, the shearing action hadn't yet completed the job, but the tiny bit of metal in the ring post recess was pulled somewhat downward towards the bottom of the ring post, nearly ready for separation.
their only true virtue--if you can call it that--is in using them in a light recoiling varmint rifle where one can employ the only "redeeming" feature they afford (which is at the same time their achilles heel)--to be able to bring the ring axis into parallel alignment with the barrel axis, in the quest to obtain near perfect alignment for shooting small, narrow bodied critters at longer distances. with a little work, in some cases i've been successful in achieving this type of alignment with dual dovetails, as well as other non-adjustable systems.
they will always have their place--with the varminting crowd; those who set up rigs with "period correct" scopes/mounts/and rings; traditionalists, etc...
that being said, there is more than a hatful of better mount systems out there, and a chap will be in far greener pastures by employing their use instead.
