Sub caliber groups typically have extreme spreads less than bullet diameter; often called a "one hole" group.
What does that mean?
It has to do with measuring groups by the widest distance from the centers of the bullet strikes...nothing to do with bullet diameter.Means there's a bench rest guy at work. "Less than bullet diameter" groups, I think, has more to do with how the BR guys measure groups. Never have figured out how one can shoot a .0077"(current, 5 shot, 100 yard, BR record.) diameter group with a .308" bullet. https://kriegerbarrels.com/smallestgroup
One hole groups is just that. All shots make one hole. Not "no distinct separate bullet holes", but all holes are touching. The gun rag writer's ideal of a clover leaf group with 3 shots.
"...If I do my part..." Is about the shooter. No coffee jitters, good concentration, good breathing, sight picture and trigger control.
Never have figured out how one can shoot a .0077"(current, 5 shot, 100 yard, BR record.) diameter group with a .308" bullet
I was shooting in Maine yesterday too--one of the rare days it hasn't been blowing 30 to 50 mph lately.I was pleased to shoot what could be considered a "bullet-diameter" 3-shot group yesterday with my factory Rem 700 ADL, .223 in factory dress, Leupold 3-9X, but pillar-bedded/floated barrel, using unfired new Starline brass and Sierra bullets in 30 degree weather, off an old Hoppe's rest at our club range in Augusta, ME. I won't try to cram the photo here, but posted it on another board that is less restrictive on file size. I've shot groups that good with my better rifles, but this one was done in 30 degree weather and without spacing shots. Load was a Sierra 52 grain HPBT, 26.0 grains of Varget. I fired several groups without consideration of barrel temperature or cooling. Most were under 1/2".
reynolds357 said:A "one hole group", according to above definition, would measure 2x the dia of the bullet, outside to outside. A "one hole 308 win group would measure at max .616".
If it happens occasionally, it means that the shooter/rifle/ammo combo is pretty accurate. Even with random chance helping all the variables line up just right, resulting in the occasional group that's much smaller than average, the shooter/ammo/gun combo still need to cooperate to get all the shots into the right ballpark or there's virtually no chance at all of getting a subcaliber group."If I do my part. . . ...
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A common reason for shooting a few shots into a sub caliber group. Sub caliber groups typically have extreme spreads less than bullet diameter; often called a "one hole" group.
What does that mean?