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Extraction and ejection issues


Eastcoastlaxin

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hello all... After completing my build a few months back, I finally got out today to dial in scope and send some rounds down range.   I quickly found out that I was having issues.  1st shot without mag (had gun in a led sled) went fine.  Second shot free hand casing did not eject and new round in chamber with spent round.  Figured it maybe a gas issue so I adjusted the Syrac block with a single round until bolt locked back.  Next few shots casing would not eject, just laying on top of magpul magazine.  Last shot, casing still in chamber, new round jammed against spent round, not completely striped from mag.  I am running a Shadow Ops Weaponry NiB BCG, heavy buffer in a Black Rain upper/lower with a Rainer Arms Ultra Match Barrel.  Running BCG well lubed but not dripping with oil.  Ejector spring seems fine and ejector pin has good tension when pushed in.  Any and all help is greatly appreciated... 

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East     nib's are known for problemos while new and rainier barrel chambers are super tight too...so then you also got a heavy buffer....why a heavy buffer on a new untested rifle? and what spring?  Oh...did you blow air down the muzzle with chamber blocked to see if you are getting air to the gas tube/ gas block? did you shotgun open the rifle and drop the bcg down the barrel to see if it almost goes into battery and no interference with the gas tube?

you got the new gun tight blues prolly..... okay the drill is....one round in the mag charge it up dont ride the charge handle...fire....it must lock back for this first function check.........so what ammo? hope its got some power and not steel cased....open up the gas block...its most likely undergassed....its gotta lock back before you go looking at mag probs or any other prob.....again why the heavy buffer on a new weapon?.....ive never ever had to go to any other buffer than a standard buffer...yes ive changed springs around,but after the rifle was running......lube it up shoot good ammo one at a time...then report back...give the nib bcg and the tight azz barrel some break in time         Ooops....so it did lock back? went and reread......you have some different mags? and what brand?

Edited by washguy
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I thought I read somewhere that the heavy buffer was a must for 308.. I still have the original that I can change out.  I'm shooting 147(?) g ammo from Wally World.  I have the equipment to reload my shells.. Just eating up trash for the brass.... I have not tried the air test but will do tomorrow.  I'm gonna try some mobile one oil and run the BCG wet. Is it possible that I have over adjusted the gas block and am getting to much gas back which is causing the BCG to move to fast??  Just spit balling here.... Has to be a simple solution that's why I'm relying on you guys!!!  Love this site and the wealth of info and willingness to help others out..

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East     so the heavy buffer you have is a slash's heavy buffer and his spring? and you have a regular 308ar buffer and 308ar spring that you can use,,,need more details on that....you need some decent ammo too that would help.....I would say that the gas port size is fine on the barrel to run the gas block wide open        Wash

 

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So a little more testing today... I looked through my receipts and the spring I am running is a JP Enterprises polished carbine spring and a standard dpms  carbine buffer.  I took apart the bolt assembly and removed the extractor pin, cleaned and oiled, and reassembled.  Soaked the BCG in mp7 oil and loaded one round in the magpul magazine.  When I fired the round, it did not eject and I had to pull the charging handle pretty hard to get the spent casing out.  Research and testing ended at that point as the frustration got the best of me....  The rim of the casing is scratched up but I can't tell if that is because of the ejector or a result of the bolt cycling back onto it.  

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Are there issues with the JP Springs?  I did notice today when I was cleaning the ejector pin that it is pretty tight.  I can push the pin in on my ar15 but not on this 308.  How much resistance should be on the spring? Should I be able to compress it a little with my thumb?  I could cut a coiI off to lessen the resistance.  I have read numerous discussions on the Shadow Ops BCGs... I sent the bolt to Ranier Arms for headspacing when I bought the barrel so I don't think that is the issue that I am having.  I'm going to order a new extractor but they are back ordered.  Anything else I'm missing? I am trying to trouble shoot this issue one thing at a time.  Thank you for all the responses and suggestions so far. 

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JP spring... say no more !

East I believe  that Dane is referring to the JP buffer spring     The chambers are tight on the Rainier barrels...you can put a lil flitz on a bore mop and drill...and polish a lil ...you never did answer the question about the airflow coming thru the gas tube....is it?   is the bcg clear of interference when dropped in?       Wash

Edited by washguy
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Wash.. Thanks again for the help and I haven't done the air test yet, my neighbor has my compressor but I will get it back tomorrow when he is home.  When I run the air test do you suggest a rag or something in the chamber where the bolt would go or should I take the bolt out of the BCG and try it that way?  Also another thought I had while driving home from dinner... When I shot it for the first time yesterday I had to take the mag out to get it to lay in the lead sled... It cycled fine... When I shot it the other times there was a magazine in it.... Does that make any sense?  I have spent some time replaying this whole incident in my mind and it just dawned on me about the magazines...

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Wash.. Thanks again for the help and I haven't done the air test yet, my neighbor has my compressor but I will get it back tomorrow when he is home.  When I run the air test do you suggest a rag or something in the chamber where the bolt would go or should I take the bolt out of the BCG and try it that way?  Also another thought I had while driving home from dinner... When I shot it for the first time yesterday I had to take the mag out to get it to lay in the lead sled... It cycled fine... When I shot it the other times there was a magazine in it.... Does that make any sense?  I have spent some time replaying this whole incident in my mind and it just dawned on me about the magazines...

Heres what I do......without a muzzle device on and the chamber plugged with a rag or lil finger  put your mouth over the muzzle blow and with the other finger feel the air coming from the gas tube of course the bcg isnt in the upper...of course the upper is off the lower...and I move the loose gas block around till the most air comes down the tube then lock the gb down...and dont tell anyone you gave your rifle a bj

 you could have a mag problem what mags do you have...try some different ones...but unlikely?     Wash

check the lips of the magazine to make sure they are not colliding with the bolt carrier with the magazine installed in the rifle. Also check to be sure that the lips are not pinching that portion of the bolt that rides between them.

 

 

Edited by washguy
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 If your fired case is sticking in the Chamber , inspect the Chamber for any imperfections & if rough , do as Washguy described with the Flitz . The Chamber doesn't have to be a mirror finish , but it should not be overly rough . Some times the finishing treatment on the Barrel can make things a little tight .

  I have a SOW BCG , NIB coated & its working fine . No amount of spring pressure on the Extractor will pull a fired case from the Chamber , if its too rough or if there are imperfections in it . 
 Blowing air can be of some use , but I prefer to measure the port holes to make sure they are properly lined up . Most of the Gas blocks seat flush with the Barrels Gas block flange , mostly all you have to do is line up the Gas Tube correctly in the Upper Receiver & they are good to go .

  You should be able to push down the Ejector , even on a 308AR , if its too stiff & unable to compress( also if its too weak ) , it can also cause Eject/Extraction issues .

Edited by survivalshop
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Thank you Survival for the input, the ejector pin cannot be pushed in with my finger but i can push it in with a casing if I slip the base of the casing under the extractor and rock it back until casing is flush against bolt face.  I did what Wash suggested but took it a little further.  Just got done totally disassembling, cleaning and reassembled gas block, tube, and bolt.  Went for a test fire with a new PMag... Single shots with mag in will eject casing 10 feet away at about 2-3 O'clock but with 2 shells in magazine, bolt will pick up second shot but firing pin doesn't engage... pull the trigger and hammer isn't "cocked".. I did change out the JP Polished buffer spring to the one that came with the DPMS handle assembly.  Making some progress here but.....

A few side notes...  The bolt catch pin doesn't hold when i manually open the breach, I can get it to open but if I move the rifle, the catch pin release and the BCG slides forward to close.  I also noticed that when I was shooting single shot from mag, BCG wouldn't lock open but I could slide it back and BCG would lock open with empty mag.  Syrnac Adjustable gas block is fully open so I don't think it is under gassed.  It is a DPMS 308 lower build kit so Im assuming it should work properly..  I am running a Black Rain Upper/lower set.

I checked the way the BCG slides in the upper and there is no interference between gas tube and gas key, slides smoothly

Do you think the new buffer spring isn't stiff enough to send the BCG fully closed after rifle is fired?

With all your help, I am getting to the bottom of this and I appreciate everyones input and time to help me figure this out...

 

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East    here's an old post from Survival          

Posted 24 Jun 2015 · Report post

  Could we have a photo of the Bolt Catch in the Lower Receiver , with out the upper on it  ?  

 

  Check on the outside of the Upper receiver & see if there is any brush or wear marks , by the Bolt Catch area . You can use grease or some kind of marker , as to show where they are contacting. Put a thin layer of grease on the top area of the Catch & close the Upper onto the Lower  & there should be some grease where the Catch came in contact with the Upper .

  The Bolt Catch can be altered if it is making contact .

Also you sure you got the ar308 parts kit with ar308 bolt catch?    whos trigger group? did you put the disco spring in correct? did you put the hammer spring on the correct way? did you check for debris in the fire control group?   you got air now...good going    get you a metal mag too you have the plastic pmag now right?        you gotta get it to hold back    Wash

if it were me i would order up some metal 308 mags and have them on hand .......also time for pics

ruler next to buffer and ruler next to buffer spring and a shot of where your bolt catch is making contact with bolt when held open (no mag)  ruler gong inside of buffer tube...how deep?  and maybe need another bolt catch

 

 

 

 

 

 

Edited by washguy
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Do you think the new buffer spring isn't stiff enough to send the BCG fully closed after rifle is fired?

With all your help, I am getting to the bottom of this and I appreciate everyones input and time to help me figure this out...

 

Try an Armalite Buffer Spring it has 34 coils and is stiffer than the DPMS buffer spring which has 30 or 31 coils.

I have a problem with  installation of part of a system. (I.E. JP light weight bcg ,spring and buffer.) It works great  if you use all of their parts together. If they are used as individual parts problems happen.

 

Also with a fired round, put a brass in the chamber , remove bcg. Plug the end on the barrel and get a can of air , insert the little red tube into the gas tube inside the upper recever ; Then blow the brass out with a quick burst of air. If it sticks ... check gas block alignment  or rough chamber !

Hope this helps.

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Ok boys here it goes... I took some pics of the requested info but I noticed when I was taking a picture of my trigger assembly, the trigger spring was above rather then under the trigger (what a dumbass for not double checking when I assembled the first time) so I reassembled the trigger assembly, put and empty mag in, pulled back the charging handle and the bolt stayed open... Imagine that... By the way..only used the JP spring on trigger, not hammer spring, it is original DPMS hammer spring.

Here are the pics of the buffers, springs, and spring depth.  I also took pics of the trigger assembly, the bolt catch with a mag in and one with no mag.  I think the trigger spring blunder was causing a lot of my issues.. I will fire it this Thursday or Saturday and report back... 

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East    like I suggested the way the fire control group is installed can fubar you....so that was one problem the trigger spring...but in the first pic looks like you have the hammer spring in the wrong way....the legs should be coming off the bottom  of coilnot the top you have it installed wrong like you had the trigger spring so to speak...you need to look at that diagram closer in the instructions or got get a pdf of the system installed the right way...you are in fubar mode. with the hammer spring on like you have it ...it will fire or maybe not fire take the hammer out of the lower and make the legs come off the hammer like whats in the picture of the instructions

the 2.5 inch is the correct buffer length should weigh bout 3.8 ozs use this one

the 111/4 inch buffer spring is the correct one to use with the 2.5 inch ar308 buffer  use this one                              not the  10.5 spring

the bolt catch is holding the bolt in a correct manner    good job

my buffer tube is 7and a tad inches  same as any ar15 car buffer tube       Wash     

Edited by washguy
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