Calif Hunter
New member
I have a MKI 1903 Springfield with the original 4-groove barrel. When the barrel is clean, it shoots 2-3 inch groups at 100 yards. After 20-30 rounds, though, it shoots one inch or less. The barrel looks shiny, but could it have small pits or something that "fill in" with copper after shooting it? I know about fouling shots and all that, but 20 to 30 rounds? Does anyone have any ideas or experience with this? Thanks!