50 Caliber Barret is an anti-tank gun, if it hits you or anything for that matter there will be either a VERY big hole or nothing at all. And even if it misses you the bullet has a air bubble that's pretty big, and will rip your face away from your skull. NOT to mention that the recoil is so bad that you have to BOLT the gun down. If you shot the croc with it you wouldn't be able to tell whether or not it was Gustave.
Over all I would advise against using a 50 caliber.
P.s Sorry a little late, you guys kinda moved on from the 50 cal but I wanted to throw that in there.