Any info on C3 Defense lower receiver

[Bret]

I was at a gun show in Atlanta today. A company called C3 Defense was there selling their products. They had some lower receivers on closeout for $89. The guy said these were milled from a block instead of forged. They were discontinuing this version and will be selling a new version that is exactly the same except that the trigger guard will be part of the lower. It looks decent, so I bought one. I searched, but couldn't find any information. Does anyone know anything about these lowers?
http://img402.imageshack.us/img402/2897/c3defenselowerleftview.jpg
http://img829.imageshack.us/img829/9512/c3defenselowerrightview.jpg

[pinzgauer]

A company called C3 Defense was there selling their products. They had some lower receivers on closeout for $89. The guy said these were milled from a block instead of forged.

This is essentially a Sun Devil lower, these guys apparently bought the rights & CNC files from Sun-Devil to make them. Side by side with a Sun-Devil they are identical except roll marks. They also have a variant with a steel threadsert for the grip screw.

They are local to me, and I have one of their first batch that were mfg'd by Sun-Devil but with C3 roll marks before they setup local production. (different serial number sequence)

It's a quality lower, and that's a great deal for a billet. Fit/Finish should be excellent. Sun-Devils currently sell for $169-199.

That said, expect tight P-Mag fit. If that's important go sloppy forged.

They also have a adjustable tensioner which reduces upper/lower slop. I don't run mine as snug as some, but for bench guys it's a big deal.

Some will point out they are normally 6061 billet vs 7075 forged. Others will point out that there are multiple variants of both, SunDevil uses a premium heat-treat of 6061 that is in the same range as 7075, and life is not that simple, even when comparing forgings vs billet.

Unlike receiver extensions alloy, my read is this particular issue is much overblown for lowers. (I do want 7075 forged receiver extensions for sure)

All that said... If you have buyer's remorse I'll buy it from you cash, if you are still in the Atl area. While I've mostly switched to LMT lowers, I'd have no problems using this on a build.

[MistWolf]

Most modern airframes are made from 7075 & 2024. Very few aircraft structural parts are made from 6061. In the last two years performing heavy maintenance on 737 Classic & Next Gen aircraft, I have yet to come across any structural parts made from 6061. I do not recall installing any structural parts made from 6061 in any of the C-17s or MD-11s I built in all the years I worked for McDonnell-Douglas/Boeing. 6061 simply isn't as tough as 7075.

While in the Air Force, I did make many "black boxes" from 6061 to hold test instrumentation & equipment, as it's more ductile than 7075 or 2024 and can be bent using a smaller radius without cracking and it's weldable. (Strangely, while I have made many "black boxes", none were ever painted black. They were always painted orange.)

Forgings are stronger than parts milled from a billet. Grain density in forgings is greater and flow follows the form of the part giving it greater resistance to breaking from stress. That's one reason certain structural parts that could be made by bending a piece of flat stock, must instead be made from angled extrusion.

The AR receivers doesn't take as much stress as other, typical receivers and those AR receivers made from 6061 billet may work just fine. But I have also been told there are examples of AR brands that use lesser materials and processes that work just fine too

[pinzgauer]

The AR receivers doesn't take as much stress as other, typical receivers and those AR receivers made from 6061 billet may work just fine. But I have also been told there are examples of AR brands that use lesser materials and processes that work just fine too

I deleted all the alloy info, as your are right.... it does boil down to just that point.... does it meet the TDP or not?

But as I understand things, it is more complicated than just 6061 vs 7075, as the heat treat makes a huge difference. 6061 as used for most equipment panels (bending, etc) is quite soft. 6061-T651 is not, and is right up there with most 7075 alloys in strength. Some will argue for certain applications that it's preferable over 7075 as it's as strong as all but the highest heat treats of 7075, and is less inclined to fracture. Less Brittle. Also better corrosion resistance, weldability, etc.

Largely moot for me, as I've gone back to 7075-t6 forged for my serious rifles. Not due to problems with sun-devil, just easier to buy complete lower from LMT, etc. that and the fact that I don't want M4C denizens to make fun of my buttery soft lower receiver! :)

[MistWolf]

Milling an AR receiver from a 6061 billet won't cause the rifle to explode, but I think an AR receiver forged from 7075 is the better choice. Cheaper too.

You are correct that heat treatment & temper is very important