The BECC - Breech-loaded Electro-pneumatic Constant-air
Cannon.
After running through several variations, this is the latest version of
the BECC, with a new PMI Trracer grip frame, T-section connectors, and
new paint. Neild developed this breech loading system several years ago,
and at the time it was the only one of it's kind (as far as we could locate
anywhere), where before loading was accomplished down the muzzle on most
air cannons. A 5 second video of the cannon firing is available on the
BECC
page.