Inferior 6061, half threaded castle nut? - DoubleStar Strongarm Pistol Tube Assembly

If you by any buffer tube it should be 7075. It is twice as strong. They came out with 6061 tubes for commercial spec buffer tubes specifically. In that instance they were twice the thickness so it was probably an acceptable substitute. Now many manufacturers use 6061, but none of the big name high quality companies do, for very good reason. 6061 is half the strength of 7075. Also the castle nut that came with this kit is the worst castle nut i've ever seen. It isn't threaded the entire length of the nut only on a small portion at the end? I'm currently trying to sell this kit I never even installed it.