I have my first AR(got it used in a trade) and just returned from the range. My first impression is one of disappointment. My AR will not feed itself. I get one round and a click. Then I have to manually work the charging handle. I get one round and a click. And here we go again. It was clean and it had a light coating of oil on the bolt carrier and mechanism. There is no dirt in the chamber/ bolt area. I am shooting factory Remington 55grn FMJ. I tried a 20rnd Brownell's Mag(Brand new) I tried a 30rnd Stoner Mag that I received with the rifle. No change. Any suggestions to making this thing fire semi- auto rather than single shot? Also, how do I lighten the trigger pull?