In PA for small game animals you gun with a shotgun you need a plug or as some people call them a “duck plug.” Sometimes you might buy a gun that does not already have a plug so then you have to go buy one such as this one from Remington.
That was my case when I found a 12 gauge Stevens Model 77h shotgun at a flea market that did not already come with a plug. Always looking for a new job for one of my favorite “hammers” I turned turned to 3d printing.
After getting the basic concept and dimensions online I was able to fairly quickly make a design. I have published the files on thingiverse.com. The design seemed to work well enough and print quality does not matter much in this case since its hidden from view most of the time.
At the time I printed it on my Monoprice i3, but these days I would recomend a person using something like an Ender 3 if for all the modern upgrades it has.