SpudFiles

Is it possible to use 2 chambers using 2 sprinkler valves, one for each chamber? I would have a blowgun trigger coming out of the top of each of them with a nipple and pull both triggers simultaneously. I think this would cut down on the size of the gun by having 2 smaller chambers instead of one big one and allow for safer high-pressure fires since it eliminates a lot of fittings needed to have 2 separate chambers. Not to mention the faster air flow with 2 1" sprinkler valves as opposed to one.

I'm using sprinkler valves one way or another, I'm just figuring out the best method to make 2 work at the time.

Pulling both triggers "simultaneously" probably won't be on the time scales air cannons work on.
You'd be better off plumbing both sprinkler valves into one blowgun and running a length of small bore tubing to connect the chambers.

Take this as inspiration for how to handle a two chamber/two valve system, just swapping the Supah-valves for sprinkler valves, and the sprinkler for a blowgun.