Would there be a problem if you used 22 WRF ammo in a marlin made to use 22 WMR ammo?

Answer 1

YES

AnswerI partially agree with the person who said "yes". Due to a difference in cartridge length, a .22 WRF (Winchester Rim Fire) may not function in the magazine of a gun built for the .22 WMR (Winchester Rim Fire Magnum). However, I was told by a gunsmith years ago that firing the old Remington .22 Special round, or the .22 WRF round, would be acceptable in a .22 magnum. My brother and I shot up several boxes of each in Ruger single-action .22 magnum revolvers and they worked fine. I doubt, though, that they would work properly in a magazine-fed gun, as the different cartridge lengths might cause feeding problems. This is pretty much a moot point, though, as both the WRF and Remington .22 Special rounds are hard come by, if you can find them at all. They are expensive too, as they are so out of date that cartridge collectors tend to buy them up. There's really no point anyway, as the .22 Magnum outperforms both of the older, outdated rounds by a significant margin, and costs less to boot. So, they might cause feeding problems in magazine fed guns, but they work fine once you get them into the chamber of the gun in question. Whether a particular manufacturer would approve of this practice is another matter.

-- Answer --

The second answer is exactly right. The .22WRF and the .22 Magnum are the same case diameter, but the .22 Magnum is slightly longer.

-- Another Answer --

If you have an older rifle chambered for the .22 WRF, a .22 WMR shell MAY load, but DO NOT attempt to fire it with this more powerful cartridge. Excess use of the shorter WRF in a WMR gun may cause enough chamber erosion that the longer cartridges may no longer chamber easily. I have seen .22 S-L-LR guns that would not chamber a long or long rifle cartridge after excessive use of shorts.

Answer:

According to "Cartridges of the World" the 11th edition, you can safely fire 22 wrf in a 22 wmr. Check it out, but i have not tried it. I do, however, sell and deal in ammunition for a living.