JDW, I have not been able to accurately measure above .790 until I recently started using the $495 Galazan gauge. However, over the years, we have used some shade tree measures which have proven that Parker Brothers, before the mid 1890s, used 9 gauge bores in ten gauge guns. The measures were right around .800. In 12 gauge guns, same time period, Parker used 11 gauge bores, measuring from .745, some as large as .750. Most collectors of early Parker guns agree that about 1894 or 1895 is the cutoff period for the larger bores. Some of these early guns also have square cut chambers for an exact length of brass shell. Apparently, back in those brass shell days, more attention was paid to exact shell length. When I have some time to measure some eight gauge bores with my new toy, I will report the results. At this time, however, I have not proven the accuracy of the gauge in the larger bore sizes.
