I don't know what the length of the bar is or how far apart the balls are. Any distance greater than 10", in my opinion, is not a good idea, in case the bore is not straight. The one ball is better because you are only referencing one point, not two.

None of these gages are good for shows, as Damascus stated, most sellers would not like their guns taken apart with the possibility of being dropped or banged against something.

I've made a few different ones and like the Galazan's type best. I can do 16, 12 and 10 ga. breech to muzzle by flipping the barrel and setting the distance wherever I want and read from top to bottom rib.

Last edited by JDW; 03/17/13 12:45 PM.
David