8-Bore;
I was quoting that 1 1/16" from memory from back when this topic was on the Lefever forum. I did just go & pull it out & re-checked it though. I didn't get precise but just layed a 6" machinist scale acroos the pins & that measurement is spot on, whether I check center to center of the pins or from same sides of the pin holes in breech. Height of the breech from flats to top is 1 1/8" & width of breech is 2 1/8", or twice the pin spacing. Many guns, including some of my other Lefevers, will have a pin spacing of less than half the breech width.
