Hi All
Tried calling Rainier today but couldn't get through, I'm sure they're packed on a Saturday. First I'll describe my rifle then I'll explain the issue.
Rainier billet matched ambi upper/ lower AR-15
Rainier Precision match grade BCG
American Trigger Corp trigger
Rainier (Rock Creek 5R ) 18" INTERMEDIATE length gas system barrel 1 in 8 twist, 223 Wylde.
Syrac Ordnance adjustable gas block
Rifle length buffer/ tube with Tubbs flatware spring. Buffer is from RRA, came with original A2 stock I had.
RRA free float tube.
Ok, now the issue I've been having. As of yesterday I have 298 rounds through this rifle. Yes it's been cleaned, I'm pretty meticulous about that stuff but don't clean every time I shoot.
Since I built this rifle I have always had issues with the BCG staying open on an empty magazine. It will never do it with 55gr rounds from any manufacturer. I have ran a lot of FGMM 69gr and had few but some issues using that. Yesterday I was trying to dial the rifle in with Federal Fusion 62gr that I want to use for coyote hunting and with this ammo I could not get the BCG to hold open on an empty mag either. I started with the gas block closed all the way and would shoot one round then adjust the gas block a couple clicks, of course the bolt didn't move with the gas block closed but as I opened it the bolt would cycle but never would stay open on an empty mag. I had two FTF's during this session also that left live rounds with dented cases. I continued shooting with the gas block full open, accuracy is awesome by the way, it's a great rifle and great barrel. I shot a total of 60 rounds all shot in 3 shot groups. The last 3 groups I shot (3 shot groups) the BCG started staying open on an empty mag but not 100% of the time. Keep in mind the adjustable gas block was fully open. I'm not sure what is causing this issue. My thoughts are: Gas block issue? Today I put a standard gas block on the rifle and I will shoot again on Tuesday and see if that fixes it. Could it be an issue with having an Intermediate gas length system, full auto bolt, rifle length buffer/ spring combo? When I changed the gas block today I did some quick measurements and it doesn't seem like the barrel was dimpled wrong leading to a gas port/ block misalignment. There is a small gap, maybe .020-.025 between the back of the gas block and the step where the barrel goes to larger diameter which I believe is correct for installation of the plate for fixed forearms. I am sure the set screw on the gas block was seated perfectly in the dimple also. I look forward to hearing from the Rainier guys but any other members that wanna add their thoughts would be great too. Awesome rifle, Awesome barrel too. 1/2 MOA if I do my part.