That is mostly correct. The 1873 used the thick head cartridge that was .135" thick on most cartridges. The Hadley device on the 1873 allowed using rimfire cartridges from 22 up to 38. I've never seen a 44 rimfire barrel offered in any Maynard catalogs. The misunderstood centerfire Hadley device allowed firing the centerfire equivalent of the rimfire cartridges in the rifles. They were already centerfire. What other purpose would they serve? Hadley barrels will only work with the Hadley device because they are shortened at the breech end to allow for the thickness of the device.

The 1882 used standard rimmed cartridges and for the 22 rimfire barrels used an offset bore that was moved up about .050" to allow the firing pin to hit closer to the rim in order to discharge the cartridge. The early 1882's still used the high spur hammer that blocked your vision at the instant of firing and the firing pin held in place with a cross screw.. Later versions had a lower spur hammer and threaded nut to retain the firing pin..

Thanks Guys! I knew someone here would sort this out for me.