All the extra energy of a mag primer is useless if its ending up in your breach instead of the barrel. CCI209Ms come out very dirty and Fed209As are not too bad but they build up carbon kinda fast. I got the same results in all my DISC based rifles with several true Lehigh NFPJ conversions. Win209s and WinT7s came out shiny. Shimming the primer pocket for a shorter primer is always an option if you feel the need for a mag primer in a Knight/Lehigh bare primer system.

I can use either Fed209As or Win209s in my Savage but it does not head space on the nose of the primer. I use both depending on the powder im using. Both come out with a slight amount off soot. Both have been reliable with powders harder to ignite than BH209 in a less efficient plug than the Knight/Lehigh design.

I dont typically use a 8lb sledge to drive a nail but i guess you could.