zimtuff, sorry I can't give you much advice on the problem with the primer cap, they are one of the worst designs I have ever seen, I spend countless hours trying to get one to work, swapping heaps of needles and caps around and sometimes I can get them to work and sometimes I don't. This happens with new caps and needles, they really are rubbish. You have to put the needle up to the light, one end has a pretty dodgey looking sort of point, which is not central and I think this could be part of the cause of the needle sticking. I'm sorry I do not have a fix for this crappy design
