This has been an interesting thread, especially point about the thumb-screws blocking the ejection port, whether for ejection or loading the magazine.
I have a bunch of different kinds of rings on my rifles, but still have quite a few Weavers, for various reasons. So I went through my collection, looking at all the rifles that have Weaver rings. Turns out I have 10, all with the thumb-screws on the right-hand side. But they don't block any part of the ejection port on any of the rifles, because they're in front or behind the port, despite me not paying any particular attention to that possibility when mounting the scopes.
In fact the scope's windage turret has far more potential for "blocking" the ejection port in all of the rifles, especially the taller turrets on many of today's scopes. Yet have encountered very few instances where even that caused any ejection problem, and none has blocked easy loading of rounds into the magazine.
