some disassembly pictures can be found here. Disassembling, cleaning, and reassembling a Kel-Tec SU-16B rifle
Last edited by mrtank; 01-14-2010 at 12:57 AM.
I'd love to try my hand at building something like that, but after the AK parts drought last year, I'm trying to figure out something for when AK bits get too scarce or expensive to make it worthwhile to build instead of buy.
I picked up an 18" bar of 1-3/4 square 1018 today. Now to find the best deal on an AR barrel extension...
I thought I saw where you were working on making a bolt. If you can do that, then you should be able to make a trunion of sorts. I'd make one with only 3 or 4 lugs. Here's a link to a guy that made a 98 mauser receiver out of pre hardened 4130. Login
Ive considered a barrel extension/trunion for a while that would use a bolt action sized lugs and a custom bolt that would fit it. there are bolt heads for various bolts that are sperate and avaliable and just build my own damm Semi auto design of rifle from scratch.
There are several sets of "build your own .50 caliber rifle" plans out on the web. The Maadi-Griffin ones are typical. They all use a screwed-on barrel extension and a simple round bolt.
You could make your extension out of 4140 or 8620 round bar and press it into a piece of cheap 1018 to make a trunnion. Two or three lug layouts would be easiest. (the Barrett .50 and Leader Dynamics .223 use three lug bolts)
Milling the bolt lugs is not that big of a deal either.
Heck, broaches to broach your own 8-lug AR extension wouldn't be that expensive.
Yes, custom broaches are rather spendy things. The Mauser-type receivers are broached as are many other classic firearms receivers.
There are work-arounds that may solve this challenge such as using a horizontal or vertical shaper with a home made bit to carve the needed internal or external slots and grooves. The bit resembles a lathe bit and is ground for the specific application... by hand if need be.
The uniform spacing of the locking recesses can be established using a dividing head or perhaps a rotary table.
For the machine-tool-challenged fellows I might suggest trying a die-filer machine for some of those inside "grooves".