im sorry if this has been posted before but i recently found a way to get ammo on a ray gun
hopefully you guys know how to get 2 ray guns, if not:

1.buy a ray gun from random box and pack a punch it
2.let the scientist take you ray gun, then buy another from the random box
3.have a different weapon in your hands when the scientist is killed
4.you should have 1 ray gun and 1 pack a punched ray gun

im pretty sure there are other ways to do this, but while on the rail glitch this is what i done:

1.put the ammo on both guns to 20/70
2.hold the non pack a punched ray gun in your hands
3.down yourself
4.get revived by a team mate
5.you should have full ammo on your non pack a punched ray gun

please inform me if you find any variations to this glitch 8) [/font]