Manufacturing Processes The overwhelming majority of lower receivers are made of aluminum. But first, what are those numbers in front of the aluminum? Naturally, there will be a cost difference between the two. However, is more corrosion resistant. When planning your build, think about how much that strength is worth to you. The difference nowadays between and is so minimal that we like the peace of mind that comes with
7 Best AR Stripped Upper Receivers  - Pew Pew Tactical
Overall, a stripped lower receiver only contains machined holes and compartments to help these parts fit snug when assembling. It must bear a serial number and its sale and purchase are regulated by law. Using a stripped lower receiver has its own benefits. The reasons behind this are its low price, ease of installation, and the capability for customization. A stripped lower receiver is much cheaper than a complete one. However, once you have to buy all the assembly parts, the price will of course rise up to at least that of a complete lower.