Outstanding information Gentlemen! We now know that the Marines were using the Allin system as early as 1870! It was accepted knowledge that the Marines were not issued the trapdoor until 1884, immediately deploying to Panama with brand new guns, but that piece of info needs to be changed to "did not become standard issue until 1884."
The assault performed by 650 Marines and sailors on Kangwha Island in 1871 left 243 Koreans and three Americans dead. Five artillery batteries in all had fallen, and 481 pieces of artillery were destroyed. I had taken it for granted that the Marines and Sailors performed this assault with the .50 caliber Rolling Block, but read in Leatherneck Magazine 20 something years ago that the assault was performed with Springfield .58 caliber Rifled Muskets-and this was in 1871!
This latest info shows that the history of Naval Service small arms is still being written!