The lock type is of the back island variant with non-rebounding locks(John Stanton devised an advancement in 1867).

http://doublegunshop.com/forums/ubbthreads.php?ubb=showflat&Number=329313&page=1



https://www.gunsinternational.com/guns-f...un_id=101167800
Beattie w/ firing pins on the hammer faces.

Cheers,

Raimey
rse