I'm thinking having ammo around headstamped .243 that's .1" short to the shoulder may not be such a good idea.  I'd planned on using GI, but I have some .243, and on down the road someone else could make theirs from .243, if I was to go with the Niemiller idea.  I thinking that having such ammo around would be more hazardous than leaving the rifle in .243!  I'm finding other similar 6mm wildcats too, some old some new.  Just having the loading gate engraved is sounding like a better idea to me.