Re: flipup caps
Wow, I don't feel so bad now. I got those caps for an ACOG, they don't say BC on 'em, but they aren't any different. Cap just snapped off at the range, very first time. Others have lasted several months, but only the bigger ones on larger scopes --and this was several years ago when I got them. Butler Creek used to have a good name, and if I'm not mistaken, some Carribean military uses their stocks on Mini-14's, kinda like "A-Team".
Rubber would be GREAT. I mean just awesome. A nice, stiff rubber. Nylon might not be bad either.
Didn't know Tenebraex made flip caps? They make the ARD or killflash and a new sunshade. But I didn't see caps. The ARD won't keep the dust out, if anything you now have to remove that to clean the glass. I don't use 'em all that often either, but I keep one on an ACOG and a RX01 reflex sight. Mostly because they don't break and I had 'em, and you need one to accomodate a flip cap on most ACOGs.
I'll check in here again, I'm interested to see what you guys come up with. Please do post how those caps work out for you.