To add more confusion, I mounted a 50mm objective scope with Warne medium rings. Had plenty of clearance on the front end for flip open scope caps; ocular too. The ocular isn't particularly large; about "normal" ; these have all been Alaskan Guide models. Just about every Handi I have thrown glass on, I think the score is 6 so far, have mounted with medium rings. All have been at least 40mm, most have been 44mm with adjustable objectives. After the first one with low rings (good idea, bad choice) all have been mounted with medium height rings, either B-Square or Warne, using the factory mounts. The one I put high rings on will be retro fitted with medium, once I find the time. Hammer clearance is a consideration more so than barrel diameter. Bull or Ultra, rimfire or HB .204, doesn't seem to matter. I would like to try the quad ring from Weaver, but haven't taken the time to order a set.