As far as posting on the forum, just use the main long gun forum.
A break barrel single shot is awesome for tinkering around and experimenting with ammo. A 22lr will shoot shorts, longs, rat shot, and even nail gun blanks with your choice of projectile(s) in front of it. You can pull bullets and do the same shenanigans with larger calibers, but if you blow yourself up don't come crying to me. š¤£
They are also about as reliable for the duration as you can get. Decades after the collapse of society š when even the Glocks have quit working that single shot will likely still be going, even if you do have to fabricate a new firing pin along the way.