Never saw a 7X57 on anything but a "long' action. However, Mauser once made an "intermediate" action that was used on one of the South American military Mausers that was chambered in 7x57.
I thought it was a standard length action.Wouldn't mags be defined as long action?Either way it's a great cartridge.My first deer rifle a Ruger M77 7x57 is still my favorite.
The only other action for the the 7x57 was an Intermediate mauser. If I recall though it was only about 1/4' shorter, and the standard mauser handles longer cartridges anyway. Definitely a long action only cartridge.