two words…
Super Soaker
shuts up my neighbors stupid bassets, and doesn’t hurt them, in fact the neighbor told me it was okay to soak them if they annoyed me 
6:00 A.M… (deep bass) Wroof wroof wroof wroof…
6:01 A.M. MacTech wakes up, grumbles to himself, grabs S.S. and pumps it up, flings the door open angrily and glares at the bassets, levels the S.S at the stupid mutts, angrily shouts “Shut UP!”…
6:02 A.M. stupid bassets (who have been soaked before) see the super soaker and shut the frell up, and attempt to hide
6:03 A.M. MacTech goes back to sleep…
i figured the S.S. was the best choice to shut the mutts up…
the “nastiest” i’d go with the soaker would be mixing in some Habanero pepper sauce in the water for a little extra “kick”
slingshot…too inaccurate, potential to injure the dog, i may hate these mutts, but have no desire to hurt them (or any animal for that matter)
paintball marker…too inaccurate, projectile travels at roughly 300 MPH (280 feet per second) potential to hurt the dog
bb gun…potential to hurt the dog