Thank you one and all for the help and suggestions.
My solution, with a little counseling, was to simply replace the Slixshot (high$$) with the factory nipples (El Chepo) which all the caps that won't work on Slixshot because Slixshot are engineered for Rem #10 fit just fine. I have a rather large inventory of CCI, RWS, and a couple of tins that may be collector item makes as i have never heard of the maker but look fine.
At one time I had a die to make caps with beer can aluminum and match heads. If I can find it that should work just fine jut no match heads.
This will work for practice draw, for trigger control, does not hurt the gun and make a very satisfying POP.
Problem solved.
Yr' Obt' Svt'
Bunk