I'm not using smoke bombs. I'm going to drop a morter round down their chimney pipe, and blow their fat little eardrums out. That's no different than using a commercial propane/oxy pest removal device, other than being less destructive to the privately developed earthworks. Then I'm gonna stand on the bank with friends, and play "valentine's day massacre".The OP’s suggestion of using smoke bombs is illegal.
Working from memory it’s illegal to take game by aid of smoke and fire.
That being said, I don’t know if beaver are considered game or a nuisance animal.
I’d sure query the local GW before going down that path.
As has been said, 3-4 330 body traps will get them every time.
At that point we'll just be eliminating nuisance animals which have caused significant financial burden.