The most common 25-20 is the Winchester for the Model 1892 lever action and Marlin even had the
25-20 Marlin loading which was still a 25-20 but different powder and bullet

The original 25-21 and 25-25 were used in single shot rifles with black powder.

Of interest, the old 28-30-120 is still used in single shot rifle matches as quality 7 mm barrels
with different twist are available