These buffer tubes are made from 7075 NOT 6061. If you find a better deal then the buffer tube is more than likely going to be 6061, which is an inferior metal!
Stock Features:
Magpul CTR Stock Mil-Spec Black
Mil-Spec Buffer Tube Kit Features:
Mil-spec 6-pos buffer tube w/ mil-spec anodizing, type III hardcoat, Class II