treefarmer Posted January 6, 2014 Share Posted January 6, 2014 I am considering a new build. I have been reading specs. on different receivers. What is the difference in 6061 vs. 7075? Thanks for your help. T.F. Link to comment Share on other sites More sharing options...
Pat Miles Posted January 6, 2014 Share Posted January 6, 2014 Do a Google search for both. Look at the ASM material data sheet for both and compare the hardness, shear strength, etc.. Pat Link to comment Share on other sites More sharing options...
openclassterror Posted January 6, 2014 Share Posted January 6, 2014 7075 is harder and heavier, with better corrosion resistance after anodizing. 6061 machines easier and is lighter. Most serious AR companies use 70xx series aluminum for upper and lower, whether forged or machined from bar stock. Link to comment Share on other sites More sharing options...
co-exprs Posted January 6, 2014 Share Posted January 6, 2014 Who makes AR receivers out of 6061? Link to comment Share on other sites More sharing options...
warpspeed Posted January 6, 2014 Share Posted January 6, 2014 Who makes AR receivers out of 6061? A number of the billet receivers come that way. I've yet to see a forged one but I'm sure they exist. Link to comment Share on other sites More sharing options...
openclassterror Posted January 7, 2014 Share Posted January 7, 2014 Early Armalites and Colts (prior to M16A1) were 6061. Before they discovered the effects of galvanic corrosion in high humidity jungle environments. Since then, only companies who are too cheap to buy 7075 but are milling from billet (fancy word for bar stock). None of the forges will make them from 6061 unless you special order a run. Link to comment Share on other sites More sharing options...
fastshooter03 Posted January 11, 2014 Share Posted January 11, 2014 7075 costs twice as much as 6061. It is stronger than 6061 in bar form. According to McMaster: 6061 yield strength 35,000 7075 yield strength 56,000 Nick Link to comment Share on other sites More sharing options...
The Donald Posted January 11, 2014 Share Posted January 11, 2014 There are some cast lowers out there. Olympic made cast lowers at one time, so did Hydra-Matic (GM). Olympics looked OK, but Hydra-Matic look real crude. Link to comment Share on other sites More sharing options...
openclassterror Posted January 11, 2014 Share Posted January 11, 2014 (edited) AR lowers are not heavily stressed parts, as evidenced by the success companies are having making them out of various polymers. The only place I have ever personally seen a plastic lower fail is across the web where the buffer tube is threaded in because the owner fell on the rifle and used the stock to break his fall. Other than that, hammer and trigger pin holes wear if the pins rotate. The only real reason the industry has abandoned 6061 is the corrosion problems because it reacts with the steel parts in very humid or salt-air environments. In a dry air desert environment you will never see any drawback from 6061. (Other than anodizing it doesn't quite seem to ever come out truly black.) Edited January 11, 2014 by openclassterror Link to comment Share on other sites More sharing options...
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