I have built a couple of .22RF doubles. My personal gun was built on a very petite framed Kettner 9x57R double rifle. Obviously, I did not want to modify anything on the gun that might cause trouble with the 9x57R, including reshaping the firing pins.

I built a whole new monoblock, though were I to build another, I would use a shoelump, like on the 25-20 above. I built the monoblock so that the bores were moved in and the centerfire strikers hit the outside of the .22RF rims. This could be done either by moving the barrels out or in, but by moving them in, it made the monoblock more petite. In a .22RF, smaller is better. I just use CCI Mini-mags all time and it shoots great (about 1.5" at 50 yards - at least minute of squirrel). Because the pins are rounded for the centerfire ammo, I occasionally (maybe one in 100 rounds) have a miss fire with the .22RF. I can live with this. While it could happen at the worst possible time - like with a rouge, charging rabbit - I doubt it will be seriously life threatening.

This is a really fun gun to shoot, and frequently gets shoot as much at the Elephant Hunt, as the big bore doubles.

Ellis