Speaking of big guns...

EMBED-Girl in Underwear Fires Potato Gun - Watch more free videos

Reminds me of a supposed follow-on to the M109A6 Paladin howitzer that was intended to use an electrochemical propellant. Hypergolic components are delivered by tracked carrier into gun's storage tanks; components get premixed and ignited by sparking array; down goes Frazier.

Found via Hollywood Tuna on Horny Oyster.