im was listening to a podcast and they mentioned how one of them put a tightbore in a spring single shot shotgun and that kind of wanted me to make my own gun. im open to suggestions and if anybody knows the barrel length of those crappy shotguns i would appreciate it.
doing what you want is not hard, you just have to get the right shotgun.
i got a mazuren ca870 with a tight bore in it and a up graded spring it shoots almost 400fps w/.2's
it shot 430fps when i first got it.