Paintball L.A.W. Launcher !!!
This is my homemade Paintball Light Anti-Tank Weapon. It features a breech load mechanism for the 2" Nerf Vortex rounds.  For safeties sake and general rules of scenario play, the launcher has an inline regulator to regulate the output pressure of a normal paintball tank, down to under 100psi.  There is also a safety over-pressure blow-off valve.  It's fairly large and cumbersome, but the accuracy and range is awesome.  Paintball scenario rules allow for 230fps projectile velocity, but at 190psi, this thing can accurately hit a target well over 100 yards away.  

Obviously, it's not meant to fire at a human target, rather to fire at bunkers, buildings, and CP (command posts).  

At Splatbrothers R.A.W. Series game, Operation Starlite, this launcher had it debut and achieve the first general kill/CP kill of the day.  I, also managed to take out the entire tower structure and eliminate over 20 opponents in the process.  This thing is a barrel of fun...

Here are a couple of videos:
LAWs Testing #1
LAWs Testing #2
LAWs Testing #3

Unpainted LAW sans paintjob...
Painted
Breech open

Me taking a shot!!!
Mini-Me and Goofa (OMM Teammates)