I picked up a hammerless Mortimer & Kirkwood rifle recently.  The buttstock was broke off, but the action is good.  Finally got time to take some pictures of it.  Similar to the one Rodney posted pictures of, but mine does not have an external cocking lever.  Looking at the piece of original stock, one can see that it was originally a hammer version with an external lock plate.  I can also see the area where the lock fit into the receiver has been filled in.  This pretty much follows the 1877 patent drawing shown in DeHaas' book.  
Bruce

Thanks for sharing. Kool rifle.

I got the buttstock of this Mortimer & Kirkwood repaired using the portion of the original stock that came with the rifle.  I wanted to use it to keep showing off the fact that it originally had a side lock.   Here are some more pictures.

A chamber cast revealed a modified 45-90.  It uses those cases, but is set up for a .452 bullet
  
Bruce

Looks good Bruce. I had a D. S. Cole that was chambered like that with that bore size also, and a early Remington Creedmoor that had that bore size in 44-77.

Now that's what the best-grade restoration work looks like.  Many pats on the back, Bnelson.

Bill Lawrence