Yeah, the Weaver's used to come with screw-on caps, but of course that was before I bought mine a few years ago.

As for rimfires, if you really want to know how tough a given scope is mount it on a semi-auto and run about 200-300 rounds through it and see if it still holds zero. Many won't no matter what they cost. Also the reason I really don't have much interest in them...well, other than maybe a S&W M&P15/22 for a fun gun.