If you have access to 15mm flares, screamers or bird bangers these allow you to shoot them out of a 12 gauge flare gun. you just load a 209 shotgun primer and that serves as the lift charge, no additional powder. These will work in a break action shotgun but wont work in a semi auto or pump.
BETA: G£OCK & WE$$ON 38mm
G19 gen 3 style RXM frame
26.5mm Pump Action Flare Revolver