I been out of the AR building game for a long time. Back when i built my first AR there was only one place to buy from and that was Sarco. Now you have 100's of places to buy from! Here a while back I bought some AR lower parts, I asked who made them, and i didn't get a strait answer. These parts were in bulk trays at a Gun Show, I see that a lot of dealers say mil spec. parts, so does that mean they are mfg. to Military Specs.??? I know that there are easy ways to tell if the spring are weak and if the roll pins are soft, but how do you know if the trigger group is hard or soft, do you drag a file over each part? How about the bolt carrier and bolt? I am sure that a lot of these dealers all buy from certain mfg's. I can't believe that every company has there own foundry!!! Yes there are the HIGH Dollar parts, but I would think that there are stock parts that are better than others???
I would be great full for the advice.