I use my 12X12" the most.
When I first bought my targets, I bought 4",6", 8", 10", and 12" sizes, some round, some square, some 3/8ths, some half.
I sold all but the 3/8ths 12" squares, and bought a couple more. If I shoot any at 2-300 yards, I just spray paint dots in several places on them,
