What do small bullet holes mean?

[Webster]

I was recently doing load development at 100 yds with a .308 and noticed a group where the bullet holes were smaller than other groups. The group was small but not tiny and was perfectly symmetrical. Is this a load I should try to tune into something smaller or just treat it like any other group? The group on the left vs group on the right same bullets.

Might have something to do with how the paper tears? Is the paper tight or loose against the backer board? I'm not used to seeing that much black around the holes? Just looked at my pile of about 50 targets. Out of about 250 groups about 10 had black around the holes. Interesting in a 5 shoot group all 5 holes are either clean or black. Seems like there shouldn't be black rubbing off the bullets? Even if the bullet was had a slight wobble where would the black come from?

Just re-examined the holes they are smaller but the bigger holes are clean cut without flaps of fuzzy paper. All the small holes have big fuzzy edges closing the holes smaller. The difference is very noticeable from the back showing how clean or ragged the hole is.

The NBRSA official targets are made from a paper that makes a bullet hole with sharp edges. I print my own with computer paper.