I have been given my great-grandfathers rifle, a Marlin .25 rimfire. I'm trying to find ammo. Can anyone tell me if it takes the long or short round?

That's Stevens 25 rf. The only Marlin that I know if that uses it would be the Mod 27s. THe ammo has been obsolete since 1942, I think some may have been made in Canada for a bit after that. THe 27s was chambered for the long round and could shoot the short round as a single shot.

Thanks wiley. You are right on target, it is a 27s. Thanks again for your info.

Another way to proceed here would be to have the barrel rechambered & headspaced for 25-20 as the bore diameter is the same. You would also need a centerfire firing pin and cartridge carrier.

I have an extra Marlin 25rf barrel if such a project appeals to you. Please PM if interested. SW