I tried to swap trapdoor locks between two rifles, because one is being repaired at the gunsmiths and I want to shoot both rifles in the meantime. When I put the other lock in, the hammer doesnt rest on the firing pin, but has enough momentum when fired to reliably fire . Can the position of the hammer be adjusted to fall foreward a little bit farther? Will any harm be done if I shoot it as is? Thanks! Joe S

Joe,
Are these both the same model Trapdoor? When you say the hammer doesn't rest on the firing pin do you mean that the hammer pushes on the pin a little but doesn't bottom out on the breechblock? If that's the case I'd be very concerned because that means something else is stopping the hammer fall, possibly the bridle in the lock itself. If so, a few hits and you've busted the lock.
Can you give more details about the two different rifles you have?

Hi Gunboat, thanks for the reply

The cut down rifle is apparently a cadet rifle, the buttplate is quite a bit narrower than the other one. The lock that came with it is being repaired. The other rifle is a garden variety 1873 rifle. It had a new stock on it when I got it, which I replaced with an original. God only know how many other parts have been swapped in and out over the years. Don't know what else I can say about it. I think I will just use the original lock that came with the cut down, just to be safe. Joe