Ooh, Rusty. FN49. Very nice. Predecessor of the number one rifle, the FN FAL. There's obviously nothing "wrong" with the 7X57 but I really honestly believe the 6.5 X 55 Swedish is a slightly better cartridge. In Europe the Swedish round is actually used in target rifles for long range work. I think they are probably a tie in stopping power on game but the Swedish cartridge is going to be more accurate (all else being equal) and shoot flatter. The slightly smaller bore, higher potential velocity, and better accuracy leaves you with a round that has real potential to be used for varmint hunting as well as a superb deer and antelope round. The 7mm Mauser would be slightly better if you were going to stretch one of them upward and shoot an elk. The slightly heavier bullet would be a better choice although for elk I lean toward something considerably bigger (one of the .30 Magnums, .338, or even the all around king, the .375 H&H). Of course my standard deer rifle right now is a Remington 700 in .350 Remington Magnum, handloaded with a 225 gr. spire point bullet. You can see I like using a big bullet so that I can shoot from any angle (that little buck this year ended up getting shot perfectly from the tail end). I've always wanted some kind of lightweight 6.5 X 55 Swedish that could become my number one deer rifle. Maybe a little Sako action or one of the Ruger Number One single shots. Something I could carry all day and never even notice but that would have the accuracy and power to kill a little Okie whitetail at 300 yards. And if it likes to knock over coyotes as well, that's a bonus.
Gregg