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.
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.
2) There is no "higher grade" of 6061 or 7075. There are just different levels of heat treat. 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 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.
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.
2) There is no "higher grade" of 6061 or 7075. There are just different levels of heat treat. 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.
