For some reason and a reason I do not understand, the more common #11 nipples manufactured today, like the Hot Shot - Red Hot - the post has been reduced in diameter so that it no longer hold #11's snuggly. In fact the new nipples are so loose simply turning the nipple upside down often ends up with the cap falling off.
I think I have found the answer...
My first attempt was to order some RWS nipples from RMC Sports. They came in the mail on Tuesday. They certainly worked better than the more famous brands but in my mind the cap still came of to easy.
So next I went to Track of the Wolf to try some AMPCO produced nipples....
SUCCESS!http://www.trackofthewolf.com/Categories/TableList.aspx?catID=14&subID=171&styleID=785&PageSize=25&Page=3TOW offers both the AMPCO Bronze RST-A and the Stainless RST-I both of these are 1/4x28 for American made rifles – but they do offer the other sizes also.
The nipple I placed on the AMCO in the picture is in place correctly – it fits so well it would be very difficult for water to get under it to contaminate the cap or the powder load.
Downside…. They caps do not come off easily…