TitoR Posted February 28, 2014 Share Posted February 28, 2014 Last week i had to open the gas block because the rifle would not cycle Remington white box, which in the past worked fine with the current setting. Since the gas block was almost fully open, I thought i needed to open the gas port in the barrel, so i was getting ready to drill the barrel. As i started to disassemble the upper, i found gas leaks as evidenced by the accompanying photos. So, will this evidence of leakage enough to cause the rifle to stop locking back? Link to comment Share on other sites More sharing options...
Dan Sierpina Posted March 1, 2014 Share Posted March 1, 2014 I seriously doubt it was the cause. What was your ambient temperature when shooting? Was your AR well lubed? Link to comment Share on other sites More sharing options...
TitoR Posted March 1, 2014 Author Share Posted March 1, 2014 I'm in puerto rico, so it was humid and hot, 80's. Gun was well lubed with fireclean. Gas block was open 4 1/2 turns out of 5 turns i measured for full open, essentially acting as a non-adjustable block. Thoughts? Link to comment Share on other sites More sharing options...
Steve RA Posted March 1, 2014 Share Posted March 1, 2014 Try some different ammo, see if that affects the operation any. Link to comment Share on other sites More sharing options...
LoganbillJ Posted March 1, 2014 Share Posted March 1, 2014 How old is the build? Any chance your gas rings on your bolt are worn and loose? How smoothly does the bolt move in the carrier with the cam pin in? Link to comment Share on other sites More sharing options...
TitoR Posted March 1, 2014 Author Share Posted March 1, 2014 I replaced the gas tube and will go test it again and report back Sent from my iPhone using Tapatalk Link to comment Share on other sites More sharing options...
fastshooter03 Posted March 2, 2014 Share Posted March 2, 2014 Yes gas bleeding is normal around the gas block. You might be able to green loctite things up but I don't know if it will hold the seal. Nick Link to comment Share on other sites More sharing options...
kurtm Posted March 2, 2014 Share Posted March 2, 2014 I'm not so sure i would be drilling on my rifle or even taking it apart because a bargain brand ammo which is known to vary wildly in velocity suddenly wouldn't work in my rifle. I do admire the style of it though! Link to comment Share on other sites More sharing options...
TitoR Posted March 2, 2014 Author Share Posted March 2, 2014 Kurt, not my typical troubleshooting, but if you review at my post history, this issue is ongoing with my setup. The mushroom at the end of the gas tube is completely gone too, and this is not a high round count gun, hence the tube swap.. And i agree, Remington white box is crap, but it is crap because it typically is below spec, not over. Since my gas block is already fully open (rifle gas), then I want to increase gas volume to allow more adjustability of the system. But, since there was possible evidence of a gas leak, i wanted to verify if this is the source of the problem. So, by changing that one variable, now I am going to adjust the rifle again to my typical load and compare how much i need to close the gas block with my typical loads. If it require closing the gas more than before, we may conclude the gas leak was sufficient to affect reliability with the remington crap. With current ammo shoetages, i need my gun to,eat anything that is available. Sent from my iPad using Tapatalk Link to comment Share on other sites More sharing options...
kurtm Posted March 2, 2014 Share Posted March 2, 2014 Mushroom gone = bad alignment between tube and key, and a rough gas key interior. Still not enough to choke a properly built rifle. Gas leak at gas block is actually the gas following the pushed in and pinned gas tube, and not block leakage. The point I was trying to make in my flippant post which raised your ire ( sorry about that) was there are plenty of things to check and fix before you go thermonuclear Link to comment Share on other sites More sharing options...
Doug H. Posted March 3, 2014 Share Posted March 3, 2014 (edited) Here is a shot of the gas port on my 20" JP barrel after about 7000 rounds. Looks way worse than yours and it still ran like a clock so I don't think a little gas leakage at the block was your problem. This was a factory build and had not been removed till I installed a new barrel last month. Doug Edited March 3, 2014 by Doug H. Link to comment Share on other sites More sharing options...
TitoR Posted March 3, 2014 Author Share Posted March 3, 2014 Kurt, no ire on my end, just posting more info for help on troubleshooting. Like for example, your comment on the mushroom. The tube on my rifle is straight and is not binding when passing over the barrel nut or thru the upper gas tube hole; basically it rattles a bit when i remove the bolt. So, maybe the interior of the gas key is rough, which I haven't thought about. Also, in comparison to how much leakage is shown in Doug' pictures after 7000 rounds, mine seems not ordinary since my rifle has about 1000 rounds. My main concern is that my rifle's gas system seems to be marginal, or controlled by the barrel gas port. Why? Gas block is open all the way, and if we assume the gas leaks are not significant, barely staying open with off the shelf 223 ammo (55 gr tula, remington, american eagle). Any dirt and it stops locking back. For example, i have a 22 conversion that I used during my last outing, and after running 200 rounds of 22, the rifle started having trouble locking back with 223, and I already have the gas block wide open. BTW, i was constantly alternating between the conversion and 223, and it was Remington white box that day. Options I see, assuming leaks are not significant: 1. Drill barrel port, allowing more adjustability with AGB, keeping current setup jp light buffer, jp light bcg, jp spring, or 2. Change from jp rifle to CAR buffer spring (maybe a taran tactical light spring) Thoughts, recommendations, am I heading the wrong way? Sent from my iPad using Tapatalk Link to comment Share on other sites More sharing options...
kurtm Posted March 3, 2014 Share Posted March 3, 2014 Well first off is it a Franken gun? I'm thinking yes. Have you checked the buffer to make sure the roll pin that hold on the polymer buff at the back hasn't started backing out, dragging on the spring? Have you made sure the bolt carrier moves freely between upper and lower with no spring or buffer in it? Have you made sure your charging handle isn't bent a little? When you put just the carrier in the upper and run it forward is the a pronounced drag on the carrier when the key goes over the gas tube? You shouldn't feel any drag and maybe even a slight click when they mate. Are you sure your carrier is a good one? Are your gas rings in good shape? Is the cam pin in good shape? Is something caught under your trigger causing the hammer to drag on the carrier? Of the ammo you listed only one is know to be "in spec" and that is federal. Have fun! Link to comment Share on other sites More sharing options...
MickB Posted March 3, 2014 Share Posted March 3, 2014 To expand on what Kurt said about checking the bolt carrier/gas tube interface. there are two checks to perform; 1) With muzzle pointing down at 45 degree angle, drop the bolt carrier group into the upper. Does the bolt lock up when running forward under gravity? if not, then check for gas tube binding. 2) Remove bolt from carrier. Slide the carrier forward and feel how the carrier key interfaces with the gas tube. Is there any drag or movement of the gas tube at all? if yes, then adjust the gas tube using a large flat bladed screw driver till there is no movement. This assumes that the gas block is properly aligned. Align the gas block FIRST over the gas port on the barrel and THEN align the gas tube. Never align the gas tube by moving the gas block left and right. Mick Link to comment Share on other sites More sharing options...
TitoR Posted March 3, 2014 Author Share Posted March 3, 2014 Kurt Great questions and here are the answers: Franken gun? - YES Rainier lower, noveske upper, nordic rifle gas barrel, miculek comp, jp low mass buffer and bcg, jp buffer spring, jp AGB, ACE stock and milspec bolt, cam pin, firing pin, JP EZ Trigger/spring/speed hammer/safety/hammer and trigger pins Buffer roll pin? - OK, not protruding or binding with the spring, it is a JP LMOS buffer Charging handle? - not bent and it moves freely, is not binding or dragging with the gas key. Outside surface a little rough, so I may sand it smooth. Binding of Tube as it goes into key? - tube moves slightly to go into the key, but no binding or dragging. Just moving sideways withing the gap it has as it goes thru the upper hole. Does it have to be perfectly aligned? I may align it to avoid unnecessary wear on tube mushroom. Good Bolt Carrier Group? it is a JP low mass, bought new, so I do not expect it to be a problem. What are the signs of a bad one? Gas rings: On the 45 degree test, the BCG/Bolt goes in almost completely (tested with a dirty gun). I attribute it to tight gas rings, not the tube/key interface. Cam pin: goes in easily and is moving freely Something caught under hammer causing drag on BCG? - Trigger area is clear BCG movement between upper and lower with no spring or buffer? - Here is were I may have a problem but maybe not. As I was doing this test with the rifle assembled, sans buffer and spring, the bcg will stay back in the buffer tube. I had to jerk the rifle for the bcg to move forward. This is caused by the hammer dragging under the BCG, just under spring tension of the hammer. I imagine this is normal, since the bolt cocks the hammer when it travels to the back. What would you consider abnormal dragging of the hammer with the BCG? Thanks in advance for your insights. Link to comment Share on other sites More sharing options...
Steve RA Posted March 3, 2014 Share Posted March 3, 2014 I'm under the impression that when the bolt carrier forces the hammer down in the firing sequence it's caught by the disconnector and then - during the reset - is released to the hammer/sear interface. Anyway, the hammer doesn't seem to drag in a new one I just put together. When I say forced down I mean that it's inertia carries it lower than it would be if contacting the bolt carrier. It's possible my theory is wrong and hopefully, if so, someone with more AR-15 experience will explain the correct sequence of events. Link to comment Share on other sites More sharing options...
MickB Posted March 3, 2014 Share Posted March 3, 2014 (edited) On the 45 degree test, the BCG should lock fully into the barrel extension.... I just confirmed on two rifles with JP LMOS carriers installed. When the gas tube enters the key, the mushroom has to enter the key cleanly. I adjust my gas tubes so there is zero, or almost zero movement of the gas tube when the key closes on it. Check if your carrier key is tight. Have the screws come loose at all? Mick Edited March 3, 2014 by MickB Link to comment Share on other sites More sharing options...
TitoR Posted March 3, 2014 Author Share Posted March 3, 2014 Steve Could you confirm that you verified that there is no drag of the hammer with the BCG by reproducing the test suggested by kurt, e.g. remove spring and buffer an check the bcg moves freely between the upper and lower without touching the hammer. If it does, then my hammer as installed is dragging under the BCG. Sent from my iPad using Tapatalk Link to comment Share on other sites More sharing options...
Steve RA Posted March 3, 2014 Share Posted March 3, 2014 Ok, guess I just disproved my own theory. I put some grease on the bottom of the carrier and let it go and it made a faint track thru the thin layer of grease with the hammer cocked. So it does rub, although mine is very, very slight drag. I've got a very slight ring around the gas tube about 1/8" ahead of the end of it and the gas key is very thin on the end. It very well may be tapered slightly on the inside of it. I've got an LAR side charge upper and it came with the bolt carrier and bolt assembly with it (and gas key) so I'm just going to run it as is. It appears that the gas tube enters the key centered, as near as I can tell. So, to answer your question, the hammer does drag slightly on the bottom of the carrier forward of the cut out area at the back of the carrier. Link to comment Share on other sites More sharing options...
TitoR Posted March 4, 2014 Author Share Posted March 4, 2014 Steve, thanks for verifying. Looks like both our guns have the same interference between the hammer and bcg. Sent from my iPad using Tapatalk Link to comment Share on other sites More sharing options...
TitoR Posted March 5, 2014 Author Share Posted March 5, 2014 Just came back from the range. Installed a CAR spring and adjusted the gas block to lock back on empty mag with Remington 55gr and dirty gun. Gas block is 80% open. So, now clean the gun and get it ready for the match sunday. Sent from my iPad using Tapatalk Link to comment Share on other sites More sharing options...
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