Just FYI...this gun is NOT built on the T. Woodward patent acme or spiral spring patent no. 651 of 1876, this gun is entirely different...its a trigger plate action....patent 545 of 1878, taken out by James Lang. James was the son of Joseph. The side plates on the Lang are dummies, on this forum we can call them BrentD plates. The lock work is entirely fitted to the triggerplate. Neat old gun.