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Posted: 12/12/2005 11:14:54 AM EDT
Ok I did a search and there was one comment that was posted in January. Anyone want to give an update on these aircraft grade billet lower receivers? Are they worth the money?
Link Posted: 12/12/2005 11:25:18 AM EDT
I saw them displayed at the Crossroads of the West/SAR show. They looked very nice!!!!
Link Posted: 12/12/2005 11:34:15 AM EDT
Are those the ones that are machined from a solid billet? I think they have an ad in the new Shotgun News.
Link Posted: 12/12/2005 11:44:04 AM EDT
I went and did some research in the mean time. For those interested what I've seen advertised at Joeken is "aircraft grade" T6 aluminum Sun Devil Mfg. lowers. If that's the case it would be 70XX which is pretty good stuff and what is considered "aircraft grade".

I don't think it's 6061. 6061 is not "aircraft grade" as it's t he same stuff that's used in car wheels and drive shafts.
Link Posted: 12/12/2005 1:02:01 PM EDT
7075 comes in T6, and so does 6061. The difference is that 6061 is weldable and slightly easier to work with. I don't know what you'd consider 'aircraft grade' but the F-15's flying around up there all have 6061 T6 hydraulic tubing. I put some of it in them. I'd consider that 'aircraft grade' by any definition.

Either metal works just fine for a lower receiver. The trick is that they are properly anodized per mil-spec.
Link Posted: 12/12/2005 3:45:17 PM EDT
I really went off of what I read which probably wasn't so complete. Anyhow yeah you're probably right.
Link Posted: 12/12/2005 4:40:54 PM EDT
I don't know who Sun Devel is using for their anodize, but there are several places in town that can do a mil-spec hard with no problem.
Link Posted: 12/12/2005 5:21:53 PM EDT
[Last Edit: 12/12/2005 5:27:19 PM EDT by j3_]
There are big differences in the properties between 7075 T6 and 6061 T6.
www.matweb.com/search/SearchProperty.asp
Link Posted: 12/12/2005 6:06:43 PM EDT
[Last Edit: 12/12/2005 6:19:01 PM EDT by BadgerArms]

Originally Posted By j3_:
There are big differences in the properties between 7075 T6 and 6061 T6.



For the purposes of the lower receiver, not really. 7075 is harder and stronger in general, but the AR-15 lower is not a highly stressed part. So long as the takedown pin, trigger and hammer pin holes are heat treated, it'll do just fine. Those are the only really stressed areas. The surface finish has a great deal to do with the overall life expectancy of the part. Since 6061 T6 takes a finish better than the 7075, it wins in that respect. It is also more resistant to shattering and intergranular corrosion than 7075. From a standpoint of what it's being used for, there is functionally little difference as I said.
Link Posted: 12/12/2005 6:21:40 PM EDT
AR lowers are not heat treated. Unless you consider the hot forging process heat treating.
Link Posted: 12/12/2005 7:02:07 PM EDT
Do they have a web site open?
Link Posted: 12/12/2005 9:48:45 PM EDT
T6 designates the heat treatment state. Otherwise it would be 6061 0 state which is VERY soft. All aluminum parts on the AR are heat treated.
Link Posted: 12/13/2005 12:45:52 AM EDT
[Last Edit: 12/13/2005 1:00:40 AM EDT by j3_]
There are 6061 T6 lowers out there. I wonder why the Government does not use it? The numbers are not even close on the two materials.

www.toolanddie.com/catalogs/SDS_fortal.htm
Make it out of Fortal an I would buy one.
Link Posted: 12/13/2005 8:17:58 AM EDT
Again, where the parts are being used is not a stressed area. You can use plastic there. You can use mild steel. You can probably use any number of softer, weaker metals. The government doesn't use it because 7075 T6 is what they specify in their mil-spec. That doesn't mean that 6061 won't work, if that's indeed what sun devil is using.

If you want to use wood for a paper weight, what difference does it make if you use southern pine or Ebony? One is harder and denser, sure, but you're holding a paper down. For what they're using the Aluminum for, the strength of the 6061 is just fine.
Link Posted: 12/13/2005 9:20:03 AM EDT
I'm a certified A&P mechanic and specialize in aluminum sheetmetal repair and fabrication. Having said that, BadgerArms=right, rest of you=listen to BadgerArms.

'nuff said.
Link Posted: 12/13/2005 11:31:49 AM EDT
Thanks. I happen to be an aircraft mechanic myself. I've worked with both metals EXTENSIVELY. I can speak first-hand from experience with 7075. It's got about three times the alloying metals and corrodes about ten times faster. Can't tell you how many '7075 cakes' I've encountered. When Aluminum corrodes, it corrodes between the grains. It can fail quickly and violently without any outward appearance of trouble. We only used it when absolutely necessary. Cracked MUCH easier than 6061 or 2024 for that matter. Sure, it's as strong as steel but you only want to use it when you have to. That being said, it sure machines and holds tolerances easier. As sloppy as the tolerances are on an AR-15, there's no necessity for it.
Link Posted: 12/13/2005 11:41:53 AM EDT
Sun Devil Manufacturing has a Web Site.
They display their Billet Lower Receiver, but no price as yet.
Here's their Link

http://www.sundevilmfg.com/


Chief
Link Posted: 12/13/2005 11:58:58 AM EDT
The guy selling it at SAR Show in Phoenix wanted $149 for a stripped lower do you guys think is it too high because I saw Stag stripped lower for $100-110.00
Link Posted: 12/13/2005 3:11:48 PM EDT
[Last Edit: 12/13/2005 3:21:37 PM EDT by j3_]
Guess I will buy one and see how holds up.
Link Posted: 12/15/2005 1:09:46 PM EDT
I should ask about a Sun Devil Discount ! Go Devils!
Link Posted: 12/15/2005 7:29:45 PM EDT
[Last Edit: 12/15/2005 7:30:21 PM EDT by raygunz]
I did a little more research and the manufacturer says it's 6061 T6. That's from the horses mouth. Does the "no dimentional inconsistency" make a big difference in strength and longevity?

They may do some in 7075.
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