I had a .243 and used nothing but good old 100 gr Hornady Interlock bullets out of it. As I recall I shot 11 or 12 deer with that rifle/bullet and all but one dropped where he stood. As for the 6mm, IMO it is a slightly better cartridge than the .243, especially for the reloader.The problem as I remember is they both came out around the same time but Remington's version had a different twist rate than the Winchester and sales for the .243 rocketed while the 6mm (I think in the beginning it was labeled the .244 Remington) sales were not up to par. By the time Remington realized their error, the .243 had a strong head start. But I am sure no deer would ever notice the difference between the two.