Theres some bickering going on at TOS about the Aluminum that Sun Devil uses in their lowers and uppers. Of course it has taken its normal nasty turn as usual. Aluminum alloys are out of my pay grade so I figured I would see what you guys think?
http://www.ar15.com/forums/topic.html?b=3&f=12&t=372468&page=1
I have built alot of SD lowers and have had zero problems.
Have never seen one broken or had issues with mine.
C4
my two cents - unless you’re in the aerospace industry 6061 vs 7075 should be a null issue, that is unless you’re really worried about all the high & low frequency vibration effects your lower will never see, tensile strength, & having ‘mil-spec’ martial. Harder isn’t always better when it comes to aluminum.
This is kinda like the 4150 vs. 4140 debate for barrels. Take it out back & shoot it.
Typical AR15.com(BS)!!! Just a big (FYI) there is nothing wrong with Sun Devil lowers. Sun Devil makes some of the best billet products around bar none. Please correct me if I am wrong, but doesn’t Sun Devil make the lowers for POF? I have two builds with Sun Devil lowers and never had one issue with them. 6061 vs 7075 WTF!!! Where do these guys come from!!lol
This is off topic and I apologize, but I’m real glad AR15.com does not accept hotmail accounts to register…I have learned a lot here with no drama. Thanks.
I believe Sun Devil responded adequately. As several have pointed out the lowers don’t see much forces that i’d worry about. Only thing that annoys me about 7000 series Aluminum is it needs a post weld heat treatment which can catch people up sometimes trying to repair something when they don’t know what they’re dealing with.
Man I really hate this being my first post on here, I rarely ever post anything online but… I had a Sun Devil lower that broke during a 3 gun event. Stress fracture, thing is I didn’t notice cause the rifle continued to function for the rest of the mag then when I hit the mag release button the bolt catch assembly popped off and then I noticed the crack going down the side of the reciever. I wish I had pics to show. That being said I’m more inclined to believe it was a fluke reciever and not the norm I have some friends that really like SD recievers so YMMV.
Did you contact Sun Devil about this situation?
That idiot named mtf or mf or mtk is a total douche.
Below is SunDevils response given out long before this came up for the umpteenth time… Read carefully. Excellent response IMO. SunDevil lowers are made quite well.
"
well guys, thought maybe we should respond to this one. some of you are stating that the 6061 alloy is inferior to the 7075, and that this is a big issue for you. there are several types of 6061 aluminum. we use 6061-T651. its the strongest of the 6061 and actually has a greater elongation than any 7075 of the same thickness. what does that mean? it means the material will have some give to it before it snaps, meaning less brittle. 6061-t651 has a elongation of 10% where as 7075 only has an elongation anywhere between 3-10% on the same thickness of material. it also has a tensile strength of 42,00 psi. there are several types of 7075 that have that same tensile strength. do you know what type of 7075 your lower is? are you sure your lower is made with the strongest 7075 available? i can tell you its not because the price you would pay would be substancually higher for your lower.
we here at Sun Devil Mfg do use the 6061 for several reasons. conturary to what has been posted, its actually a lot more corrosion resistance than 7075. it also holds an anodize better than 7075. we hard anodize are lowers making the anodize thicker. 6061 is cheaper and its easier to machine. we dont use forged molds like all other lowers. some people are claiming that a forged lower is stronger than our billet lower. what happens when something is forged. 2 parts are pressed together at extreme pressure which causes the molicules to align, creating a stronger product than say a cast part. now how do we get our blocks of aluminum? they’re not from a cast block thats for sure. when we buy a bar of stock aluminum, say 12 ft long, we get it in our desired dimensions. how do the metal companies get those dimensions? they press the metal to the desired size, just like a forge. all the strength of a forged product is there. now that we have a forged brick 8" in length we can start our machining process. this means we dont have to rely on the 3 or so main companies that supply all the other lower manufactures w/ their molds.
of course our products are a bit more expensive by a couple bucks, but i can guarentee you that you will not find another lower that has been built and has been looked over for any imperfections, quite like our lowers. attention to perfection is key here at Sun Devil. we also have the tension screw mod on our lowers. this takes out all the slop that comes from the mating of the upper and lower. our lowers are all within mil-spec. they will fit any mill spec upper as will our uppers fit any mi-spec lower. not only do we offer just flat black receiver’s, but we also anodize sets in green, blue, gold, maroon, pink, purple, and we can also coat our receivers in our Devil Coat (Np3 nickel-teflon).
we really do appreciate those that use our products and continue to give the rave reviews of them. we know that you are the real advertisement of our products and we thank you.
Posted :: 9/11/2007 6:20:36 PM EDT"
I just recieved my custom serial Sun Devil lower and may I say it is very nicely made. I think I need to order another one. This one is going on a 6.8spc build. I need to find a good deal on a Larue or DD rail.
This is not true.
A machined part has exposed end grain. This is weakness regardless of how the base materail was finished (hot rolled, cold drawn, etc).
scottryan,
Well take it up with SunDevil.
I would think they know their products better than anyone. That’s what they posted (their direct quote) I am not quite sure what you are saying anyhow?
You are speaking of machined lowers in general, however, the ongoing debate is in regards to “7075 vs 6061” (actually various alloys of EACH type).
Sounds like you are referring to the subject of “forged vs machined”
One other thing I think some folks overlook, the anodizeing on some of those fordged 7075 lowers is NOT MIL spec, Sun Devid does use the correct MIL spec HARD anodizing and its very hard as per MIL spec.
and it really don’t matter, an AR will not take aluminum to it’s point of performance like 6000 series vs 7000 series vs billet vs forged.
a jet would be the place to argue aluminum’s properties.
Yes I did contact them about it, I should have said this in my previous post but upon their inspection of the reciever they replaced for me. They didn’t give any specific reason why it was a bad reciever but they did make it right they’re CS was very good. So I have a new SD lower I have yet to do anything with. It was my first Billet machined part so now I’m hesitant to use one ever again.
They havent made lowers for POF in awhile.
Someone please tell me what YMMV stands for.
Years on the forums, and I know literally every other abbrev. except that one.
YMMV has stumped me for years…
Your Mileage May Vary.
Warrior,
That issue has been seen in standard lowers, though not quite as often as the ears breaking.
I agree. However, I’m pretty sure I am in the minority. I guess the TDP is good for some things and not for others.