I don't want to slander a site sponsor but be careful with TNA. I made a bulk order of parts from them, specifically a buffer tube and buffer assembly which was completely out of spec and caused a myriad malfunctions despite all parts saying "milspec" in their descriptions. The buffer aluminum was cast rather than machined and the spring was rubber or polymer coated, and the tube just felt cheap. To be blunt it just didn't work. This was in August of 2021. If it's cheaper than everywhere else there's a reason for that. Sample size of one but still concerning. I'd stick to U.S. made brands from RDSC, CSC, FOC, Nordic, bullseye, select and tenda when they have stuff in stock.