Chaser Posted December 10, 2014 Report Share Posted December 10, 2014 I am trying to track an issue. At this time, I've finally assembled the structural pieces of my 308 project which consists of a Mega Arms 308, DPMS bolt carrier, JP Rifles barrel assembly, and the DPMS buffer. The problem is that when I attempt to rack the charging handle it is exceptionally difficult....like two hands difficult. The bolt never sticks back, as I'm not even 100% sure it's back far enough to trigger the mag catch solidly. If I release the charging handle, the whole thing slams forward. Seats properly....but as I cycle it, I can distinctly smell "hot metal". I can't locate any wear on either the BCG, charging handle, or the receiver. Charging handle is also Mega Arms. All pieces cycle appropriately, and it's gotten slightly better with repeated applications of CLP, but this just seems abnormal. Anyone had similar experiences or recommendations on what to change? My gut feeling is that it's an interaction between the bolt carrier and the charging handle....but I'm not sure if anyone can help with recommendations on another....I don't want to just keep buying BCGs to try to "get lucky". v/r, Jon Quote Link to comment Share on other sites More sharing options...
FaRKle! Posted December 10, 2014 Report Share Posted December 10, 2014 (edited) The bolt never sticks back, as I'm not even 100% sure it's back far enough to trigger the mag catch solidly.So you're saying the BCG doesn't lock back correctly? Is the hard part of cycling the action the initial unlocking of the bolt from battery, or is it difficult the entire pull through? When the BCG is taken out of the gun are you able to move the bolt in and out of the locked position on the carrier or is it really difficult?Are you using the LR-308/AR-10 rifle buffer and spring in your PRS? Edited December 10, 2014 by FaRKle! Quote Link to comment Share on other sites More sharing options...
Chaser Posted December 10, 2014 Author Report Share Posted December 10, 2014 The full pull sucks, beginning approximately 1/8 inch back. I have been able to replicate the problem without the lower connected (pulling the charging handle/BCG back as a unit when not connected to the lower, and it still sometimes sticks). The CLP has made it able to be pulled....but it's still a fight for the entirety of the pull. I'm using the Slash buffer, 308 spring and 308 rifle buffer with the PRS. I'm trying to find the regular buffer around here somewhere, but I don't think that that's the problem. My gut feeling is an interaction between the CH and BCG....but I can't prove it. v/r, Jon Quote Link to comment Share on other sites More sharing options...
Chaser Posted December 10, 2014 Author Report Share Posted December 10, 2014 (edited) I tried using an AR-15 rifle buffer from one of my other weapons.....same problem. AR-15 buffer spring to soften the pull....same problem. Took the whole assembly off and I could get it back occasionally....but it still seemed to stick frequently. The BCG is capable of moving on its own, as can the charging handle....but the two together seem to be what I'm guessing the problem is. I just tried ordering a Raptor Ambidextrous 7.62 charging handle. I find it hard to believe that the charging handle would be the problem....but I have to try it. This is just giving me fits of insanity....lol. v/r, Jon Edited December 10, 2014 by Chaser Quote Link to comment Share on other sites More sharing options...
Robocop1051 Posted December 10, 2014 Report Share Posted December 10, 2014 Separate the upper from the lower. Does the BCG still drag inside the upper when disassembled? Inspect your carrier. Are there any unusual wear marks or scratches? Check your buffer retention detent for proper height. Check your bolt catch for tension and height. Either of those could be dragging. Quote Link to comment Share on other sites More sharing options...
Robocop1051 Posted December 10, 2014 Report Share Posted December 10, 2014 It's cheaper to try a new CH vs a new carrier. Quote Link to comment Share on other sites More sharing options...
shibiwan Posted December 10, 2014 Report Share Posted December 10, 2014 Methinks there's something not right with the upper. Probably crushed a little bit, enough to cause the bolt carrier to stick. Quote Link to comment Share on other sites More sharing options...
Chaser Posted December 10, 2014 Author Report Share Posted December 10, 2014 I think I found the problem. I'm 99% sure that the charging handle is the issue, but it is certainly involved with the charging handle. Strike/friction marks are on the lower receiver, and it seems to get a bit easier after I took the dremel to the CH. I'm going to try the Raptor....hopefully it'll work. But otherwise, I'm going to certainly grind some of the pieces down to help facilitate movement. I just hate to go grinding on stuff without a real grip on what is going on....and until I am close to getting my weapon painted. v/r, Jon Quote Link to comment Share on other sites More sharing options...
Chaser Posted December 11, 2014 Author Report Share Posted December 11, 2014 Confirmed: It is the charging handle. I ground multiple places and have managed to get it easier to charge. What a mess. I am hoping that is the ONLY problem, but it is dramatically easier. So my hope is that the Raptor ambi charging handle will maybe work a bit better. In the meantime, I'm going to keep trying to figure out how to get this to do everything I can, as I wanna see this baby ready to be operational. v/r, Jon Quote Link to comment Share on other sites More sharing options...
Croaker Posted December 12, 2014 Report Share Posted December 12, 2014 (edited) 8) Edited December 17, 2014 by Croaker Quote Link to comment Share on other sites More sharing options...
Chaser Posted December 12, 2014 Author Report Share Posted December 12, 2014 That was right where mine became an issue, when the bolt disengaged from the barrel. I ground a few mm off both sides and even the CH and it's fairly smooth now (although I need to take a bit more as she's still sticking, but I'm going to see what happens with the Raptor ambi charging handle. Who makes your receiver set? v/r, Jon Quote Link to comment Share on other sites More sharing options...
98Z5V Posted December 12, 2014 Report Share Posted December 12, 2014 Chaser, Croaker - have either of you guys shot your rifles yet? Go put rounds downrange, with the appropriate amount of lube in the new rifle. Quote Link to comment Share on other sites More sharing options...
Chaser Posted December 12, 2014 Author Report Share Posted December 12, 2014 No...I haven't. I'm not convinced that it would have cycled before I ground the crap out of the charging handle. I CLP'd it 4 times and it took 2 hands and the rifle propped on my abdomen to get rearward travel beyond where the bolt disengages from the star chamber. Racking that first round would have LITERALLY been impossible. I'd have to manually load the bolt, drop the BCG in, reassemble......try not to get it to go boom at the same time. The rifle will be going to the range within the next couple weeks most likely. I want to see how it all comes out. All remaining parts are on order. v/r, Jon Quote Link to comment Share on other sites More sharing options...
98Z5V Posted December 12, 2014 Report Share Posted December 12, 2014 No...I haven't. I'm not convinced that it would have cycled before I ground the crap out of the charging handle. The charging handle doesn't reciprocate - it'll shoot if your BCG isn't binding. Quote Link to comment Share on other sites More sharing options...
Chaser Posted December 12, 2014 Author Report Share Posted December 12, 2014 I was more concerned with the safe loading of the round. Breaking it down and manually loading it seemed a bit more risky than I wanted to get.... especially because I hadn't diagnosed the problem yet. Jon Quote Link to comment Share on other sites More sharing options...
98Z5V Posted December 12, 2014 Report Share Posted December 12, 2014 Can you lock the bolt to the rear? Fight it back, lock it, lock sticking-charging-handle forward. Load mag. Release bolt catch. Fire weapon repeatedly. Reload with full mag, repeat. That thing will break in sooner or later, without cutting on the charging handle. Shoot it, man, instead of trying to diagnose dragging on new parts on an unfired rifle. Quote Link to comment Share on other sites More sharing options...
98Z5V Posted December 12, 2014 Report Share Posted December 12, 2014 Mega doesn't put out bad parts. There's no way they made a narrow channel for the charging handle, or made a wide charging handle, and wouldn't catch that before they ship. No way. Quote Link to comment Share on other sites More sharing options...
Chaser Posted December 12, 2014 Author Report Share Posted December 12, 2014 So they told me. I can't explain what happened...whether it was a slight difference in the interaction between the bolt carrier and charging handle due to tight tolerances or what. All I can say is "It wouldn't pull. I ground the charging handle down. It will pull." I don't fault Mega Arms for things, but when I've dropped more than $4500 on a rifle.....I want it to be range-worthy, not a paperweight. So I've been doing everything I can to get the components working. v/r, Jon Quote Link to comment Share on other sites More sharing options...
98Z5V Posted December 12, 2014 Report Share Posted December 12, 2014 Can you lock the bolt to the rear? Quote Link to comment Share on other sites More sharing options...
98Z5V Posted December 12, 2014 Report Share Posted December 12, 2014 (edited) ... but when I've dropped more than $4500 on a rifle.....I want it to be range-worthy, not a paperweight. So I've been doing everything I can to get the components working. v/r, Jon I understand the frustration, man - I really do. Not trying to attack you, so please don't take it that way. Trying to help you here... Can you lock that thing to the rear or not? Edited December 12, 2014 by 98Z5V Quote Link to comment Share on other sites More sharing options...
Croaker Posted December 12, 2014 Report Share Posted December 12, 2014 (edited) 8) Edited December 17, 2014 by Croaker Quote Link to comment Share on other sites More sharing options...
survivalshop Posted December 12, 2014 Report Share Posted December 12, 2014 I have an Aero Precision assembled upper on one of their M5 lowers and a 3rd party BCG. I did all the usual break-in procedures and it still hangs up after the lugs seem to unlock. That is when I discovered my problem - when I first test fired it. I knew it was stiff and expected some FTE the first few rounds and some bolt overs while the parts mated together. That pretty much is how it started out. Of the 1st 10 rounds I think only 2 or 3 cycled fine. Each shot the extraction was better and pretty soon they were being thrown 3'@3pm. Rounds 15 thru 20 all ejected and fed the next round... the bolt locked back on the last round, so I thought it was a done deal but then shots 21 thru 25 were back to single shot & bolt overs. After 25 shots I stopped. The hard hand cycle is what concerned me to tear down and inspect. I had that bolt dripping with CLP. I have to put the muzzle on my shoe and pull with both hands as hard as I can to get it to pop free. At the moment I'm looking at the ejector lug and bolt pin-cam slot as that is where the most wear is. It will lock up almost as hard even empty, and detached from the lower. The thing that really is stumping me is that the fired cases will thunk right into a Wilson case gage as if they were FL resized and the head is right where it should be. I've never seen a gas gun chamber that tight. At the moment I don't want to go into it any more so I will start another thread in a few days after I do a little more troubleshooting. I have a 5 page long dissertation of what I've looked at so far. I've gone over just about every area on the bcg and receiver except lugs I can't see. I am in discussion with the bcg maker...so can't go into details just yet - I want to see if this gets fixed or replaced. I've ordered a cheap standard charging handle on the off chance that is part of the problem... I'll need it anyway for a spare. Have you checked Head Space ? Is the BCG NIB coated ? Are you sure its the BCG that is hanging up ? What stock are you using & are the proper components installed ( Buffer , spring & receiver extension ) Disassemble Bolt's , extractor & Ejector & clean , lubricate & inspect for freedom of movement of both components . Quote Link to comment Share on other sites More sharing options...
Chaser Posted December 12, 2014 Author Report Share Posted December 12, 2014 (edited) I understand the frustration, man - I really do. Not trying to attack you, so please don't take it that way. Trying to help you here... Can you lock that thing to the rear or not? Don't worry. I am not upset or getting defensive about that. I am grateful for the help. The interactions with Mega Arms were basically the same way..... the first person saying "you should have called us immediately rather than demeaning the process." (I emailed as soon as I noticed that it helped.) Then tried to work together to see if this was caused by an error that I made. But with it starting immediately with the BCG installed I am not sure how. I don't think it's any fault of people. ... and historically the Weird-Poop-O-Meter pegs out whenever I try to do something like this. I can lock the bolt back now or feed a round after the grinding. I want to get the new charging handle to see if that works. But I will be getting her out to the range soon, and with any luck I'll have some new stuff after the New Year. V/R, Jon Edited December 12, 2014 by Chaser Quote Link to comment Share on other sites More sharing options...
shibiwan Posted December 12, 2014 Report Share Posted December 12, 2014 Mega doesn't put out bad parts. There's no way they made a narrow channel for the charging handle, or made a wide charging handle, and wouldn't catch that before they ship. No way. I've seen this issue somewhere but I don't recall where it was. There was issue with a certain combination of a certain upper and one particular charging handle being a hair too wide to fit in the channel. I'll post it when I can find it again. Quote Link to comment Share on other sites More sharing options...
Croaker Posted December 12, 2014 Report Share Posted December 12, 2014 (edited) 8) Edited December 17, 2014 by Croaker Quote Link to comment Share on other sites More sharing options...
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