The questions you ask is what I'm trying to learn before I buy. I would like to put it in my bolts or AR guns. If I cant get max performance I will buy what I need for both. More than likely it will be on a bolt .223 and an AR .223. Would like to put on my 3006 deer rifle also if I can but not necessary.

Its not a license its a $200 tax stamp. Part of The NFA law.

I would not ever buy a .223 can for my first supressor. Its to limiting and you will not notice any extra supression.

Get a .30 cal can for your first one and use it on everything. Wait tell your next several befor you limit yourself.

The AR platform sucks for supression also you will probably need to add an adjustiable gas block to help with being over gas and reduce gas in your face.

Decibal reduction # only tell part of the story. Tone and pitch play a big part. A can can meter a little louder but may sound quiter to your ear. Deep tone will sound more quiet than a higher pitch. Yet the higher pitch may meter more quietly.

NFA talk is a good place for info. Tons of independent meter data on thst sight. Some taken at my farm. I host an event most years.