Swiss 18 mm Milbank-Amsler, 18x25RF (1867)

[bubi]

The other day, I bought a beautiful gun: A huge excellent Swiss gun, all parts with equal numbers--even the bayonet. But how to make it shoot? (My ideas are preliminary--that is why I am putting them down. I would like to have your input.) The first step to a solution was to install a .22 blank in the base of the case--but which case? The lower part of the 700 Nitro Express was my first idea--and I even found a company, which would make it relatively cheaply ($ 7.00 per case). Then I found out that they could produce the original case without the off-center hole. It will probably take months before they will be able to send me the cases. In the meantime, I wanted to think about how to drill the off-center hole for the .22 blank. The problem with a thin shell base and the .22 blank is the following: After firing, the case of the .22 opens up wide and folds over the inside bottom of the parent case making the fired blank hard to remove. So make the base thicker, something like 6 mm or 7 mm. I made a few "cases," to find out how to drill. First idea: Drill with a .22 drill along the inside of the case. The problem was then, however, that the rim of the .22 was not hit by the striker. It was too close to the center. If you moved it closer to the rim and drill through with a .228 drill, you might damage the wall of the shell. Here, the thick bottom of the shell is a boon: Drill along the inside wall of the shell with a smaller drill, then from the bottom up with drill that has the same diameter as the pilot for the counterbore (containing the rim of the .22). Then enlarge it with the .228 drill--but a little less 6 mm to form a chamber for the blank. The first drill makes a flash hole.

The original load was a 40 gram (617 grain) soft lead and expandable bullet. The powder charge was 4.5 gram (69 grain) of black powder.

The Lyman 1-Cavity Minie Ball Bullet mold 69 Caliber 730 grain is even heavier.
I got the black powder (from Switzerland) from Buffalo Arms,
the gun from Collectible Firearms,
hopefully soon the shells from Rocky Mountain Cartridge.

The idea with the .22 came from Dixie Gun Works.
Someone on the internet gave the advice to use two baked "mold" pieces of Super Sculpey to hold the cases in a vise without damaging them.

All the best to all of you.

[Ballistics in Scotland]

Nail-gun blank cartridges come in a range of different powers. So it might be that the weakest wouldn't bulge in the way you describe. I think it would be difficult to find a way of putting any sort of solid insert in the case so that it would both prevent the bulging of the blank, and stay in place. If you did, you would have to check each case after firing, to make sure that the insert isn't left in the bore. It would probably cause a ring-bulge or even a burst barrel.

One way to do it would be to make a brass or steel bushing to fit the blank, and file it down to fit against the side of the case. Then fit it with epoxy or a hard grade of silicon rubber, and finally drill the case-head through that bushing, with a long drill.

It doesn't take a lot to ignite black powder, especially since you probably aren't trying for the ultimate in target accuracy. You will find threads on these boards about making ordinary muzzle-loader caps with the paper ones used in toy guns. It might be possible to use one of these over a much smaller hole in the case head, possibly with a slight drilled or stamped recess which you could probably make with the firing-pin and the undrilled case. This is very similar to the arrangement used in the earliest centrefires. I wouldn't slam the block shut, but I think it would work. Those caps are very likely corrosive, but it takes the gun left uncleaned a while for that to do any harm, and you could minimize the effect by covering them with the self-adhesive copper tape I use to keep slugs off my potted strawberries, for the little varmints can't cross copper.