I couldn't speak to Federal primers in Krags, as there is no floating firing pin, and therefore no chance of slam-fire... but I have read about people having serious troubles using Federal primers in their Garand Rifle loads. 

This year, I've obtained 2000 CCI 34 military-grade primers for loading my Garand ammo.  I'm curious as to their comparison to CCI 200 and CCI 250 primers (I've been told that they are somewhere in between).  I may switch to these in my Krag loads also. 

Incidentally, the reason for my use of magnum primers with the IMR-4350 is purely from a burn prospective...  being that 4350 is a slower burning powder and somewhat harder to ignite than say 4895 or 4064... and the hotter flame from the magnum ensures a complete burn with the 4350.  That said, based on your results, I may revert to the standard CCI 200 for future matches if the military grade 34s don't pan out.  With the shoulder problems I'm currently experiencing, it ain't gonna hurt any to reduce the recoil some!