1873 trapdoor manufactured in 1874 then converted to carbine. The gun is in great condition and the guy I hot it from said it was cut as one of the early conversions at springfield but can't verify. The barrel cut and crown is perfect so it was done very well by skilled machinist. The barrel is exactly 22 inches and 41.3 inch total length exactly like factory carbines. I believe it was done at springfield. The gun shoots great and I had an ultrasound scan of the steel and there are zero issues, it's as old as the day it was made. 251sixtwo34452. Text for info it's a great rifle on great condition.