Hi and thank you
I realize this thread is really old and probably dead, but I too was having feeding problems with the .243 in a Mauser action and found this on the internet. Loading the .243 cartridges in the very back is definitely the cure but I was also having problems due to the base of the cartridge not sliding up the bolt face as the cartridge neared the chamber. The angle of the cartridge was thus too steep and it would bind. I have 2 other Mauser action rifles in .220 swift and 7mm Rem Mag so I looked at the way they operated. When the cartridge was sliding up toward the chamber and 3/4" was still visible, the base of the cartridge was at least 3/4 of the way up the bolt face thus assuring the proper angle to enter the chamber. I then took a file and rounded the very bottom lip of the ejector on the bolt at the bolt face. I doubt if I took off more than 0.010" of metal. The .243 base now slides up the bolt face properly, there is no binding and it feeds the entire magazine easily. Thanks for this thread as the whole thing was driving me nuts and I had no idea what to do about it. Thanks again.