Yo, 6 years later I know, but no it's not just you. I recently got to playing FO3 again and the weapon animations are definitely still broken. Garands reloading as if they're revolvers, pump shotguns reloading as if they're some kind of sub-machine gun, and sub-machine guns reloading the magazine from the wrong side (so that they're not actually touching the actual magazine, just playing with some invisible toy.) If you've found a solution over these years, I'd love to know what it was haha.