Hmm..
A. Puff of Ninja Smoke, Robo arm steals your weapon, checks how much ammo there is in there, grabs a better version and fires untill there is just the right ammmount in there.
B. Robotic techies come up with a soldering iron, Take your weapon and tinker with it before giving it back
C. Satanic blessing on the weapon
D. Divine blessing on the weapon
E. DIY Upgrade kit
F. You pull the lever, A platform rises out of the floor carrying a superior weapon with it, You throw the old one away and it hits a duck on the head. The duck died.
I would list more but soon we will run out of entire alphabets.