GunsNStuff has $55 threaded M21 bore
for "canning" the little Beretta .22lr. It's also useful for screwing on a pc of tubing, and then brazing on a ramped,serreated front sight. Weld up the top rear of the slide, fit a real rear sight, heat-bend the trigger to remove overtravel, and the M21 groups 3" at 25 yds. To get it to 2" groups takes pinning down the rear of the popup barrel, and that then requires the making and fitting of an extractor, which is a LOT more hassle.
for "canning" the little Beretta .22lr. It's also useful for screwing on a pc of tubing, and then brazing on a ramped,serreated front sight. Weld up the top rear of the slide, fit a real rear sight, heat-bend the trigger to remove overtravel, and the M21 groups 3" at 25 yds. To get it to 2" groups takes pinning down the rear of the popup barrel, and that then requires the making and fitting of an extractor, which is a LOT more hassle.