Poor quality control - Guntec USA AR-15 Builders Kit w/ Ambidextrous Safety

The take down detent pins and springs were two different sizes. Bolt catch pin was obviously too big. I tried to use them on a spikes milspec lower and had to modify parts like shorten springs or swap parts with a different lower kit. I tried reaching out to the manufacturer but they seem to be too busy to talk about it. Pitiful fit and finish for aluminium parts. Won't every buy again and will probably replace them with steel parts.