This was a toughie. It's the Castle's M18 57mm Recoilless Rifle. I've been repairing the firing mechanism (which I broke many years ago trying to figure out how it worked... what a surprise). It's a ATF-spec deact, with a bore-sized hole in the breech and permanently blocked so as to be unable to seat a live round. It will, however, seat a slightly trimmed cartridge case - which means... subcaliber device! Because it *had* a functional trigger, it's treated as a Class 1 firearm, and transfers like a standard rifle does, rather than as a Class 3 Destructive Device, which is what it would be were it fully operational. I have no intention of trying to return it to fully-operational status, though I know people who have done so. While it's illegal to make machine guns for private use anymore, you can still pay the tax and reactivate things like artillery - assuming that it is legal at the state and local level.
So, in anticipation of getting a subcaliber device for it, which would allow me to shoot it like a rifle, I decided to fix what I broke last time, which was the sear trip, which got crushed when I reassembled the breech without having adjusted it properly. Oddly enough, those bits aren't common, but they *are* out there, if you know where to look.
So, as I've been disassembling, cleaning, analyzing, repairing and then reassembling, I've been taking pictures, as I really don't want to tighten the last screw and find something sitting on the bench that I have no recollection of where it belonged.
So, here's two pics of the fiddly bits all in their proper configuration and full context.
Mikey was getting close when he said that the crank looked like it might open a breech - though I suspect it doesn't quite operate like he imagined. Argent was also close when he said "the thing that hits the thing to make it go bang" as the part in question he was referring to was in fact the part of the breech that holds the firing pin and spring - but viewed from behind. Again, I suspect it doesn't work quite as Argent envisioned, as I suspect (correct me if I'm wrong there, mate) that he saw it acting more as a hammer - when in fact it is really the axle around which the breech rotates and the firing pin is integral to the axle.
Just a reminder - this is perfectly legal where I live, and the Borg Collective you belong to may have quite a different view of this sort of thing, whereupon it sucks to be you if you share my interests. My Borg Ship (and in fact all those flying in close proximity) is supportive out here in the flyover. Some of you who live in the fringes of civilization aren't trusted to behave by your hive queens, and you should change your local structures to one where you are governed, not ruled, and live as free persons.
Don't move out here, please. We like the elbow room. Fix it where you live. Lest you think it can't be done - out here we'd been banned from private ownership of machine guns since the 1934 Union Station Massacre (which didn't even happen here...) and in 2008, on July 1, that ban was overturned.
Just sayin'.]]>