Source: http://members.tripod.com/~MichiganPaintball/barrelstuff/barreltest.html
Group Size: The
smaller the better, they are the spread of an average of 5 shots, shot at
25yds. The lower the bar, the tighter the spread.
Noise: Common Sense comes into play here, folks.
Shots/Clean: The number of shots it takes after an "artificial" break
to be able to hit a 15" square at 20yds.