Yes, I have had one now for 25+ years, a .22 Magnum Super Companion, with a 1 5/8" barrel. It has been about 24 years since I fussed with it, as it holds zero interest for me. Unless they have changed, Remington #10 caps are the only ones that will work, and that is what my original owner manual states. Other caps protrude too far out, and you are unable to insert the cylinder after loading. I've tried loading pellets and such, using light loads as a "gallery" gun. The results just plain sucked. You are pretty much stuck with using the NAA 30 gr. bullets. Velocity is very low (400-500 fps) with blackpowder or pyrodex. When 777 came out I tried that, cramming as much powder in as would fit, which resulted in a tremendous effort to seat the bullet. Velocity barely was 700 fps, and lowering the charge to enable easier loading resulted in bb gun velocity. MY GUN came with instructions that I could use up to 2 grains of Bullseye. Those instructions are no longer provided, heard the ATF frowned upon it. That did give high velocity, but wild and erratic, 1200 to 1600+ fps. Hate to think what the pressure was on those rounds going 1600 fps out of a 1 and 5/8" barrel. Accuracy was decent enough with all loads to hit the broadside of a barn, if you were inside of the barn. Lots of bullets tumbled, and left clear indications of such on paper. Very disappointed, maybe the longer barrel guns would provide better results. No complaints on workmanship, the gun is just a novelty item. When I have the opportunity to shoot, I take a real cap and ball revolver, and the NAA Companion has been occupying a drawer now for 20+ years.