KheSahnDon:
Please, Please, Please, don't rechamber or line the original barrel. Restore the gun and put out the extra couple bucks a box for .22 short.
I'm not sure, but I believe the carrier would have to be replaced to make .22LR work in a .22 short gun. I do not believe the .22LR guns will feed the .22 short out of the magazine. The carrier as far as I know is caliber specific.
JagheadGunner:
When you say .22 extra long do you mean .22 WRF? If so, CCI started to load .22WRF last year. I picked up a box of the CCI plus a box of the limited edition Winchester stuff that was made a few years ago for my 1890 in .22WRF. The new CCI ammo worked great! it was the same price as a box of .22WMRF, about $5-$6. Performance was a bit on the slow side, probably to play it safe with these old guns. It was running about 1250 fps with a 45 grain jacketed bullet. Or, about the same as my .22 LR, but with 12% more bullet weight.
My recommendation is to leave all the guns as-is since the ammo is now available for chamberings of them. A skilled restoration is all I could condone due the history and collector value of these guns.
Kent