I have a friend with a 6" Model 14 and I have shot a 8 3/8 Model 14 at bullseye for decades. My friend wondered if my longer barrel gun was more accurate so we shot both from rest with my wadcutters, and either gun routinely shot 1" at 25 yd.
So as far as the gun itself, I expect no difference. How the shooter does with the gun can be substantial. For our model 14s, if we're shooting over 1" at 25 yards, it's not the gun. Reassuring but also humbling.

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Science plus Art