Silencers, how do they work?
https://www.geek.com/geek-cetera/silencers-how-do-they-work-1617138/

How does a gun silencer work?
https://science.howstuffworks.com/question112.htm

Here's What's Happening Inside a Gun Suppressor
https://www.popularmechanics.com/adventure/outdoor-gear/a28357/suppressor-clear-slow-motion/

Here’s how the Navy wants to silence the ‘Ma Deuce’
https://www.militarytimes.com/off-duty/gearscout/irons/2019/09/04/heres-how-the-navy-wants-to-silence-the-ma-deuce/

This is what a silencer for artillery looks like
https://www.businessinsider.com/this-what-silencer-howitzers-looks-like-2017-6