At 25 feet everything out to shoot to the same place.....that's really close! Even at 25 yards the difference in grouping by various loads will be close enough for a combat revolver(I've got the target: 38's, 357"s, cast, jacketed, hot, mid range!) and a typical group with one good load should be in the 1" or less range with the iron sights. At 50 yards(open sights, supporting the gun in some way but without a machine rest) you can expect an honest 4", better with practice.

That double ear protection is a great idea.