Target practice with my air rifles was upsetting the neighbor’s dog. ( strange beast, Pit Bull head and neck on a Dachshund body. Looks like something from a cartoon or chernobyl. )To maintain the peace, I made this shooting muffler from a recycled box and egg crate foam. It sits on wood blocks ( height adjustment ) on my shooting ( picnic ) table. I can’t quantify the noise reduction but now the dog and neighbors don’t notice when I’m shooting.
Yes. Used a concrete column forming tube made of thick cardboard. Lined it with carpet. Helped cut some of the noise. Never quite sure how much.
You may want to carefully check the applicable laws/regulations.In Canada, for instance, this sort of thing is treated exactly the same as a suppressor, and thus is a "prohibited device", since the Criminal Code prohibits "a device or contrivance designed or intended to muffle or stop the sound or report of a firearm" without specifying that it has to be attached to the firearm.