i think i know why people get mixed reviews on the acs bolt. i was looking at the design of them and i tihnk some perform better than others . if you look at the rear cocking design it has more room for the spring to compress because it has a long cocking rod which goes most of the way into the bolt when the spring compresses, allowing less chance of ball break. now take a look at the imagine bolt, it looks like the cocking knob is not far from the end of the bolt like less than an inch, so it doesnt allow any room for the spring to compress. hope that all makes sence. anyways just something i noticed, anyone wanna shed some light on it?