Gary, I have his book but don't know if that is mentioned. The .410 here comes from the 12mm. walking stick gun cartridge; they freely interchange and are sometimes marked with both metric and imperial, and as such was first available in 2" black powder with a load of 5/16th. ounce of shot. The 2 1/2" cartridge followed later in about 1913 to match the BSA single barrel .410 bolt action gun which used surplus military actions; I think it was the Lee speed action. The 3" followed a few years later in the 1930's with Midland Gun Company's side by side shotgun. The 2 1/2" carries just 7/16th. ounce of shot. The 32 bore or 14mm. was also intended as a'collector's' gun and fired the same load as the 2 1/2" .410. The 28 bore with its 9/16th. ounce was the smallest real game gun at the time. Lagopus.....
