John K

Well kind people, the mystery the bolt not locking open has been solved. I received a return call from Garrett at Armalite this afternoon. He patiently and methodically worked through it. He determined that the magazines were correct and the bolt catch was the correct generation. He then asked me to back out the screw that was holding the Magpul PRS stock on about .5", insert an empty magazine and pull the charging handle back. Low and behold the bolt locked open. The screw holding the stock on was simply too long and it prevented the buffer from fully retracting thus preventing the BCG from moving rearward enough to be caught by the bolt catch. Problem fixed with a shorter screw! I cant say enough good things about Garrett and Armalite. He gave me his cell# and asked me to text him pictures of the magazine and the bolt catch so he could verify that they were correct. He said that there was a slight possibility of incompatible parts due to generation changes around the time my rifle was manufactured. A good company with great people working for them will always result in a top notch product. Thanks again to everyone that chimed in on this one.

Hi Rsquared- Thanks for the reply and the kind offer. I'm in Montgomery County. I haven't tried any other magazines but I did try varying amounts of rounds from 1 thru 10 in both of the ones I have.

Thanks for all the input guys. I will order some of the Anti Venom and send more lead down range. It's a tough job but someone's got to do it I didn't notice any strange wear patterns on the BCG and I did try both of the magazines that came with the rifle. There was no change in performance. I do love the rifle. During the break in it was busting clays at 300 yards. Many thanks, john

Hi 98Z5V. Except for a Magpul adjustable stock, Nightforce scope and an Atlas bipod the rifle is a 100% Armalite factory built original. No mods or aftermarket parts. Do you have a recommended lube? Break Free CLP, Ballistol... Thanks!

Thanks for the reply. Greetings from the not so gun friendly state of Maryland. Each trip to the range I fired 40 rounds so that's 80 rounds total. In retrospect I probably didn't use enough lube during the barrel break in. Definitely used more during the second trip to the range. The bolt catch feels pretty smooth despite the "pressing harder" issue I mentioned and I have oiled it well after that first range trip.

Hi all- Being new to the AR platform I'm asking for input or a reference to any former post concerning a failure for the bolt to stay open on an empty magazine. I have an Armalite AR10 (B) Target. Purchased new in 2013 but not shot until last week. I was doing the prescribed Armalite barrel break in and noticed that the bolt would not stay open on an empty magazine. After the break in I thoroughly cleaned and oiled the weapon but still have the same issue. I've cycled several different brands of ammo (Federal, Remington and Hornady) and am using the factory Armalite 10 round magazines. The bolt will lock open if I firmly depress the lower portion of the bolt release button to engage it. Thanks for reading. Any pointers are greatly appreciated.