The screws are the weak point on the factory mounts.
I use them on a T3 .243 and they are fine. On something with more recoil i would replace the screws or go with a Weaver type base/ring combo.
I have used them with no problem at all, the front ring has a stud which mounts in a corresponding hole so they are not going to move.
I do replace the screws with harder ones which can be purchased at practically any hardware store (or big box store). The screws are soft but I doubt that that changing them is necessary unless one changes scopes quite often as I have a tendency to do. I have noticed that after the rings have been on the rifle for a while the screws can be a bit tight this is probably caused by the dissimilar medals since the screws are steel and the rings are aluminum. In my case changing them to a harder screw is just a precaution to be sure that I don't end up drilling one out after rounding out a head. A couple of dollars well spent in my estimation.
If you are going for lightweight I doubt that you could find a lighter set of rings for a T-3.
drover