The Skeet's gage is what you want. It cost $100.00 and will measure 12 ga.and will read to about 12" into bore. You can get one from 100 Straight that measures 4 gauges, but that is $400.00, and measures to about 16". If you go to 100 Straight's web site, they list that you can get the 4 gauge set, with and pick the gauges you want. I believe that Glazan sells the same thing but you take their set of 4 gauges.

Last edited by JDW; 01/31/11 01:34 PM.
David