As a few have mentioned, a 2- or 3-day course will reveal many problems in lesser-quality ARs. Case in point, in 2008 my dad and I took an Appleseed 2-day course, during which most will fire upwards of 400-500 rounds. By the end of the first day, our kit rifles built on Olympic receivers were giving us fits with walking pins, failing springs, extraction issues, and a broken firing pin. Those issues marred what was otherwise a very nice experience. Fast forward to 2016, and a friend and I were taking another Appleseed 2-day course. I used my carbine with an LMT lower and BCM upper, while my friend used my Colt 6920, which he wanted to run because he was prepping to deploy to Afghanistan and would then be issued an M4. We burned through a lot of ammo, and had a lot of fun, but I cannot recall a single malfunction with either gun. Since my experience in 2008 had largely pushed me away from budget ARs, I was very pleased with our results in 2016.