What good isn't there in putting everything around you on fire? I got this idea for flamethrowers in brikwars.
Use: 2 (Roll of 1 and it backfires)
Instead of picking a target it rather shoots out for 6'' in a 45 degree cone. (like a minifigs field of vision) and hits everything in there. But instead of dealing regular damage, the target is set on fire, dealing 1d6-1 damage per turn after the round it was dealt. (not at the round it was dealt) lasting until the target dies... scratch that, lasting until it gets water on it. Also I think it could work if a minifig stands in fire in general. if the walk/run through it, they just take damage, without being set on fire.
Maybe also a blowtorch version that is 1 handed with 3'' in range.
Nobody expects the spanish inquisition!