“The ONLY thing about an M16 which is even a tiny bit difficult to manufacture is the barrel.”
IIRC, mine in Vietnam was manufactured by Frigidaire.
I don’t think they’ve made it past 80 rounds with a printed lower receiver before it cracked. At this point it would be more like a throw away gun.
Level of difficulty has nothing to do with the issue.
At stake is whether or not free men ought to be armed. Period.
They should; to defend their liberty from all who would abuse, usurp and become tyrant over them.
As an aside, the critical components of the AR or most any other weapon for that matter is heat treatment of proper steels. The AR bolt does not lock into the breech of the barrel, but rather into a barrel extension, which is screwed onto the barrel breech, very much like a bolt actio or most all other actio types. It, the boltand carrier are made of not too common (but not rare) steels heat treated to be extremely hard, tough and wear-resistant.
The M-16 is a weapon that must be cleaned, very often!
I recall fondly my M-16A1 in boot camp. The best part of the rifle range was actually shooting. I shot 10 bulls eyes at 500 meters. When we weren’t shooting the DI’s were putting us through all sorts of hell so we all wanted to shoot more.
The extension threads onto the chamber end of the barrel and becomes essentially part of the barrel. Never heard of anyone removing the extension, though I am sure it has happened.
Therein lies most of the accuracy inherent in the AR platforms, the bolt and barrel assembly are darn near independent of the rest of the parts.
Good write up.
The funny thing is you can’t buy an AR15.
They are sold out nationwide. Just not available. I’ve tried.
Well, there’s a couple details you sort of blipped over.
In order of complexity of manufacturing, I’d rate the parts on the AR-15/M-16 in this order:
1. barrel. Obvious. Deep hole drilling is part art, part science. Reaming and rifling can be done reasonably easily, but slowly. Getting the initial hole through the barrel stock and mostly straight is a challenge and requires high-pressure lube/cutting fluid, as well as that fluid coming out the cutting bit used for the deep hole drilling.
But for someone with some skill, they can make their own deep hole drill. It’s been done.
2. The bolt & carrier. Lots of fiddly little machining, but possible. You’ll need a super-spacer or indexing head to get this done on a Bridgeport.
3. The barrel extension. This is the bit you sort of blipped over... the back end of an assembled AR-15 barrel is a “nut” that gets screwed onto a threaded and chambered barrel. The tenon on an AR-15 barrel is supposed to be 0.6200” long, 0.8125x16TPI, Class 3 fit. The finish reamer is sunk deep enough into the barrel that a go gage sticks out by about, oh, 0.129” for a spec barrel extension and a spec bolt.
But even after machining this all in at tight tolerances (this is the part of the AR-15 that has anything remotely resembling tight tolerances), unless we used pre-hardened 4140 for the bolt and the extension, we’ve got to harden both parts and draw them back a bit. Not difficult, but not something that most people making their own are going to remember to do, and their bolts and/or extensions will wear too quickly and the headspace will open up in time.
The fastest way to get around the heat treating is to use pre-hard 4140 and then use carbide tooling to make the extension and the bolt.
When you have the extension done, then you’ll have to torque it onto the barrel to 150 ft-lbs of torque. This will result in about 0.002 of crush on the tenon shoulder and the extension. Once this is to spec torque, you’ll have to drill the 0.125” hole through the extension on the frontmost part of the cylinder that gets put into the upper receiver, then put in the indexing pin for keeping the barrel oriented correctly in the upper receiver.
Then you’ll have to reckon your gas port size, make a gas block to fit your gas tube, put it on the barrel, etc.
Once that’s done, the rest of the job is a downhill run...
When I arrived at Bragg in ’78 (2-508th Infantry, 82nd Airborne Division) I was issued an M16A1 made by the Turbo Hydramatic Division of General Motors. I always preferred the A1 over the muzzle heavy A2, and not only because of the A2’s lack of full auto – which is rarely a good thing for a grunt, but it IS comforting to have it available.