Has anyone had experience with QD uppers? I see they are reasonably priced. I plan on putting it on a complete Spikes lower. Trying to go as inexpensive as possible but, with quality components. I plan on using the weapon for keeping up with my friends that are in LE. Shoot what they shoot. The last time out I used a DPMS GI lite and I started to experience feeding problems after about 300 rounds. Hard firing on a Saturday afternoon.