Thought that I would post a few photos of a remington derringer that I have been working on. As purchased it was only slightly more than a frame and barrel. On the other hand they are expensive enough in complete form that it is worth puttering on them if you are more interested in function that factory perfect.
Luckily I was able to borrow one and copy the firing pin and ratchet assembly. I posted a couple of photos to try and show how the ratchet works. The ratchet superficially looks like it has 4 notches but it actually has 4 shallow notches and 4 deep notches. There is a point or lump on the bottom of the firing pin which rides in these notches and when in the deep notch the pin fires the bottom barrel, in the shallow notch, fires the top barrel. When the hammer / firing pin falls, it pushes the ratchet ahead 1/8 of a turn so that the notch which is top center alternates between shallow and deep. There is also a spring at the back of the ratchet to prevent it rotating backwards when the gun is cocked. The extractor is a fiddly piece to make and is dovetailed in between the barrels. I have not cut the notches for the cartridge rims yet.
The hinge portion on the top of the frame was broken off and so far I am waffling on how to repair it. I am sure that I will silver solder a new one back on but dragging my feet for the moment
Only other thoughts that come to mind is that I made a hollow end mill to form the pivot post on the back of the firing pin (out of sight) and had to grind a hack saw blade down to about 1/3 its thickness to make the thin cut for the spring on the top of the firing pin.
cheers mooncoon
Luckily I was able to borrow one and copy the firing pin and ratchet assembly. I posted a couple of photos to try and show how the ratchet works. The ratchet superficially looks like it has 4 notches but it actually has 4 shallow notches and 4 deep notches. There is a point or lump on the bottom of the firing pin which rides in these notches and when in the deep notch the pin fires the bottom barrel, in the shallow notch, fires the top barrel. When the hammer / firing pin falls, it pushes the ratchet ahead 1/8 of a turn so that the notch which is top center alternates between shallow and deep. There is also a spring at the back of the ratchet to prevent it rotating backwards when the gun is cocked. The extractor is a fiddly piece to make and is dovetailed in between the barrels. I have not cut the notches for the cartridge rims yet.
The hinge portion on the top of the frame was broken off and so far I am waffling on how to repair it. I am sure that I will silver solder a new one back on but dragging my feet for the moment
Only other thoughts that come to mind is that I made a hollow end mill to form the pivot post on the back of the firing pin (out of sight) and had to grind a hack saw blade down to about 1/3 its thickness to make the thin cut for the spring on the top of the firing pin.
cheers mooncoon
