I am using their lower. I have not a single complaint. It is mounted to a LaRue upper. They are good but the Vltor is tighter in the critical areas for accuracy. In all honesty its going to be splitting hairs. What is nice about the Sundevil is matched receivers the tension screw and they don't mark their products up into the stratosphere because they are billet. They do use an alloy that is easier to tool but its plenty tough and don't let all the hype you read about strength and various alloys, billet, forging etc fool you the receivers in ARs are not under high stress from the cartidge. Come on they fire 50bmg off AR lowers and the uppers in the 50 and other big calibers are extruded. All the stress in an AR is contained by the barrel its extension and the bolt. Think about it. Round goes in chamber, bolt locks, round goes off, pressure is one, bolt opens. Other then reciol on the stock there is no stress.It a 50calr reciol isn't an issue then all this stuff about my alloy is tougher etc is all a bunch of irrelevant info.
Posts by Test_User
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The funny thing is what makes forging strong? Its pressed under great force correct? Guess how they get those size blocks of aluminum they cut your billet receiver out of. :idea: Hmmmm Also there are differnet grades of 7075 aluminum many not as strong as top grade of 6061
Very informative and good info.snort said:Ugh, I thought I replied.
I have thoughts on the Sun Devil lower:
1) the pin holes are oversized in mine. Enough that my fire control pins were walking out after 10-15 shots. I had to put KNS anti walk pins in. I dont know if my take down pins are undersized, but my upper and lower wobble a bit. I'm going to get a new set of pins and test.
2) the oversized (compared to spec) rear of the receiver required that I hog out my MIAD backstrap with a dremel tool. It fits fine now though
3) The magwell is slightly undersized. Mags that fit fine in my colt wouldnt go into this one at all. Again, this may be specific to my lower.
Why didn't you send it back as it was obviously not within spec? Was it second hand or used where you could not? My bet is regardless if you called SD they woudl have replaced it. That is certainly not the norm for this product.
And thoughts on alloys:
1) if the gun that blew up was made of 7075 it wouldnt have blow up. 7075 is stronger than 6061. By a factor of 3. If 6061 handled it, 7075 would have too. I agree but 6061 does tend to allow for flex before failing then 7075 from what I have read but it as in 7075 is stronger in the context we are speak in
2) There is no "higher grade" of 6061 or 7075. There are just different levels of heat treat. That is what I meant honestly just didn't feel like going into it as I have a habit of long posts :lol: and the point was still the same: 'increased strength at least that is how I understood it. Certainly don[t have any expertise in the area only what I have been told and read I believe I have gone on at length about this in a prior post. If you care, search for it. There could be counterfeit aluminum with inferior metallurgy that snuck into the supply train - but in that case its not really 7075 is it? And this does happen, racers have been dealing with fake grade 8 and fake AN hardware for at least 20 years.
3) While, in general, forgings ARE stronger than billet parts, that isn't always the case. Remember billets are forged when they are rolled, and the grain structures are straight. The structural reason to use a forging as opposed to billets are that you can form the grain structure so that it is curved, and flows around obvious stress risers. Now, we take a lower forging which has a straight grain structure, and then cut a big ass hole in the center of the grain structure (the mag well). How is that any different than the billet? its not. The reason Uncle specs a forging, is that there is less wasted material, thus lower cost once the tooling is amortized. There is absolutely no reason to not use a billet in an AR platform. I agree completely and a very good explanation
Your comment about the counterfeit aluminum apparently has been an issue with the amount we seem to be getting from China. Same with barrel steel apparently the level of impurities in some batches is thru the roof.
Unless that SD is really old I woudl still give Dave the owner of SD a call. He is a good guy and I don't think wants products like that out there. In general my rule is if there is a issue I call th seller first if different then the manf. Then the manf. I think they have to be given the chance to fix and issue as even the best manf in the world can put out a POS here and there. Now if they don't correct the issue then all bets are off.
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