As you may know there is a tesla cannon hidden outside of the map when Liberty prime explodes. I used a bunch of ammo boxes to get outside the map and found out it looks like a missle launcher and uses missles as ammo. Should I keep the original one or the one I found. :unsure2:

First of all you should prove that this is real via link. Secondly , itls completley up to you, personally I find microfusion cells easiest to find

if it looks like a missile launcher and fires missiles, i would call it a missile launcher.

http://fallout.wikia.com/wiki/Beta_Tesla_Cannon But it's much easier via console commands than ammo boxes.

It's an old and very verified possibility.

Many have gotten the Prototype. Even myself.

does it shoot faster or slower than the original ?

Bout the same IMO.