Martini Henry 577-450 carbine

[Fronteria]

Unless of course it's a commercial one, so may not have a number.

Try Peter Dyson https://www.peterdyson.co.uk/acatalo...NRY_Parts.html

Purchased one from Peter Dyson.
Many Thanks for your help.
It is apparently a 577-450 MK1 Martini Henry Cavalry carbine it is dated 1877 on the right hand side of the action.