this was from a Washington DC estate tag sale. I thought it was a variation of a baby whitworth, but the twist is the wrong direction. the measurements are very close to the projected measurements John use's in his book for a 1.9". it does have a very old tag attached, not able to read but some letters of writing using an old dip pen. many of the 1.9" whitworths went to South America, but the twist directions makes me think its something else. Post war experiment? looks pre cartridge era
weight: 2lbs 12.2 oz
length: 5.38"
flats: 1.837 ( one is slightly smaller)
ridges: 1.967
any ideas