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rauchman
05-17-12, 14:17
Greetings all,

I have an idea for an Assault Weapons State friendly stock product. It's going to be based off of a rifle length buffer extension tube and I need to get some info on it. I've tried doing searches for schematics on this part and have come up empty.

Does anyone have a schematic of the rifle length buffer extension tube w/ measurements? I've sat w/ a ruler and taken measurements and read a few threads on this site, but haven't gotten all the measurements.

What is the thread pitch where the tube screws into the receiver?

What is the thread pitch for where the screw goes into the rear of the tube, for where the stock is attached to the tube via screw?

What type of aluminum is used? I think it's 7075, but have also seen references to 6061.

What is the finish used? I think it's mil-spec annodized, but have seen references stating phoshpated.

Just wanted to say a pre-emptive thanks for any and all help with this. I'm just a normal guy that has a passion for firearms, especially the AR15. I've been working in the natural food industry for over 20 years now and am making an effort to make a living from something I have a passion for. I've been talking to some machine shops (some I'm sure the regulars on this site would familiar with) and they've been very helpful w/ their insight.

So again....thanks
Warg
05-17-12, 15:07
I don't have access to the TDP, but I can answer a few of your questions


RE threading is 1 3/16x16
RE's are manufactured in 7075 and 6061, but I believe the spec calls for 7075. Colt's are 7075.
Per BCM: Hard Coat Anodized per Mil-A-8625F, Type III, Class 2


Some good info here: https://www.m4carbine.net/showthread.php?t=98675
rauchman
05-17-12, 15:16
I don't have access to the TDP, but I can answer a few of your questions


RE threading is 1 3/16x16
RE's are manufactured in 7075 and 6061, but I believe the spec calls for 7075. Colt's are 7075.
Per BCM: Hard Coat Anodized per Mil-A-8625F, Type III, Class 2


Some good info here: https://www.m4carbine.net/showthread.php?t=98675

Thank you!!!

Edited to add - Unfortunately, I think a lot, but not all, of the info in the referenced link is for carbine type tubes. Still, some good info...thanks!!!
skullworks
05-17-12, 20:17
My guess would be that you would be more likely to see manufacturers who use commercial RE's for their carbine stocks to use 6061 for their rifle RE's. I mean if they're willing to go cheap on one, why not the other?
AR15barrels
05-18-12, 00:27
What is the thread pitch for where the screw goes into the rear of the tube, for where the stock is attached to the tube via screw?

1/4-28
rauchman
05-18-12, 08:02
Thank you all, excellent info!!!
Sticks
05-19-12, 05:49
Designing your own Vltor A5 type system?

Love mine, interested in seeing what comes out next.
rauchman
05-21-12, 17:26
Designing your own Vltor A5 type system?

Love mine, interested in seeing what comes out next.

Yup! I've been talking to some machine shops on getting the buffer tube made. I've been trying to find a CAD knowledgable person for the stock design. It's getting there, but slower than I would have hoped.
rauchman
06-07-12, 12:18
Does anyone know of a machine shop that could make a custom length A1 rifle extension buffer tube? It is amazingly frustrating trying to find a place to make this part. I really figured that a shop that already makes the A1 rifle extension could easily make my part, since it's the same piece just shortened by 1.625"
AR15barrels
06-07-12, 15:39
If you provide the drawing, any machine shop should be able to quote you on it.
Otherwise, just post the drawing and specs up on mfg.com and have people submit their bids...
rauchman
06-08-12, 09:44
If you provide the drawing, any machine shop should be able to quote you on it.
Otherwise, just post the drawing and specs up on mfg.com and have people submit their bids...

Thank you!
AR15barrels
06-08-12, 10:10
Just remember that machine shops will produce what you draw and specify.
That includes every aspect of the part.
If you leave out things like concentricity call outs, edge chamfers and surface finish specs, don't be surprised when your parts are not as you expected...
arfan1
06-09-12, 15:18
but if you're changing the length of the RE, it's no longer an A1 tube.

The A1/A2 RE has had quite a bit of tests done with the rifle length buffer and spring vs the carbine buffers and tubes, and then there are variants (The A2 is longer, but uses the same A1 internal spring and rifle buffer, along with a spacer to accodate the longer A2 stock).

Carbine versions also vary, the keyed 4 and 6 position are most common, but there are also non-keyed carbine length RE's (e.g. RRA entry stock), and then new designs like Vltor's A5.

My comment is that if you're going to a new length, with standard rifle buffer and spring, you might be up against a lot of testing work.