In addition to running a lot smoother, the adjustable gas block made a big difference on what my used brass looks like - for reloading (no more swipe marks from the ejection pin). Another really nice change was the Gen 3 Little Bastard Self Timing Muzzle Brake my son got me for fathers day. The people next to you at the range aren't going to love it, but you'll appreciate not having a sore shoulder/bruise after spending a day at the range turning $ into noise.