Troubleshooting Failure to Feed on a DPMS LR-308

[Casey Simpson]

Re: Troubleshooting Failure to Feed on a DPMS LR-308


Armalite, Larue, or custom-smithed.

Big chassis AR's are simply too ticky for incompetent mass production.

 

[Mr.Maim]

Re: Troubleshooting Failure to Feed on a DPMS LR-308

I took it out to the range the day after my last post with four sets of ammo:

145-gr Federal American Eagle
168-gr Federal American Eagle
168-gr Prvi Partizan PPU MATCH
175-gr Prvi Partizan PPU MATCH

I only had time for five rounds of each... it cycled everything. Not a single FTF, FTE, jam, malfunction, anything. I'm absolutely stunned.

I had only put the backup iron sigts on because I was planning on dropping it off at Accuracy Speaks (gunsmith), but even with BUIS and using the range-provided rests I was hitting the 300-yard steel plate 4 out of 5 rounds.

I'm stunned. I mounted up my bipod, optic, monopod, etc. and am heading out to the range this morning to re-confirm. I'll report back.

 

[Casey Simpson]

Re: Troubleshooting Failure to Feed on a DPMS LR-308


Accuracy Speaks can fix anything AR-based.

 

[cramey74]

Re: Troubleshooting Failure to Feed on a DPMS LR-308

I don't know if this will help you or not but I bought a DPMS LR308 a couple years back before firing it changed the stock to a PRS put a muzzle break on it ETC...Before taking any new rifle to the range I always strip them and look for any imperfections in machining/casting process but before even doing that I noticed this gun was extremely hard to cycle to the point that I wondered what the hell do I have here and is this going to be a Turd that will not polish...upon stripping it I discovered everything was a little tight and burs all over the place so I grabbed the dremel scotch bright and polishing kit and went to town on the reciever bolt/carrier group feed ramp ETC...You could see just from hand cycling where things were touching and some of that is okay but this was excessive..It took me a little while to get it the way I wanted but when finished upon putting it all back together it was a different rifle action was smooth and at the range it would cycle every load I threw at it...I did not have to take off alot of material or anything but there were a bunch of high spots....Hope this helps

 

[.308ing]

Re: Troubleshooting Failure to Feed on a DPMS LR-308

I am glad to hear some success at the range.

I got mine back after a month and I too got the same hand-written gunsmith form. I was really upset by it because they said "customer claims failure to feed issues," as if I have the time, patience or impetus to make false claims.

I have not made it to the range yet but judging from the odd similarities in histories, it appears to me that DPMS may have made changes and simply does not want to admit to them.

Going to Range this weekend with hopes of no failures.

 

[Mr.Maim]

Re: Troubleshooting Failure to Feed on a DPMS LR-308

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: cramey74</div><div class="ubbcode-body">...I always strip them and look for any imperfections in machining/casting process but before even doing that I noticed this gun was extremely hard to cycle to the point that I wondered what the hell do I have here and is this going to be a Turd that will not polish...upon stripping it I discovered everything was a little tight and burs all over the place so I grabbed the dremel scotch bright and polishing kit and went to town on the reciever bolt/carrier group feed ramp ETC...You could see just from hand cycling where things were touching and some of that is okay but this was excessive..It took me a little while to get it the way I wanted but when finished upon putting it all back together it was a different rifle action was smooth and at the range it would cycle every load I threw at it...I did not have to take off alot of material or anything but there were a bunch of high spots....Hope this helps </div></div>

Did you have burrs on the interior of the upper receiver that were scoring the bolt carrier? Where did you find these defects? Thanks!

 

[Mr.Maim]

Re: Troubleshooting Failure to Feed on a DPMS LR-308

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: .308ing</div><div class="ubbcode-body">I am glad to hear some success at the range.

I got mine back after a month and I too got the same hand-written gunsmith form. I was really upset by it because they said "customer claims failure to feed issues," as if I have the time, patience or impetus to make false claims.

I have not made it to the range yet but judging from the odd similarities in histories, it appears to me that DPMS may have made changes and simply does not want to admit to them.

Going to Range this weekend with hopes of no failures.

</div></div>

Cursive writing, in red ink? Same 'smith. He's arrogant and won't put his name or initials on his workforms because clearly he doesn't want to be responsible for his bullshit work.

Had several failure to feed issues today. Probably six or seven out of 75 rounds. Rifle could be excessively dirty so I'm going to clean and oil the heck out of it and shoot it again early next week.

I'm calling DPMS Customer Relations (NOT technical support) on Monday to complain. This is bullshit and I think manageemnt needs to know that their gunsmiths are ASSHOLES, don't troubleshoot and work on rifles being sent in to them, provide terrible troubleshooting steps and solutions, and don't even back up their work with a signature or name.

BULLSHIT.

 

[cramey74]

Re: Troubleshooting Failure to Feed on a DPMS LR-308

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Mr.Maim</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: cramey74</div><div class="ubbcode-body">...I always strip them and look for any imperfections in machining/casting process but before even doing that I noticed this gun was extremely hard to cycle to the point that I wondered what the hell do I have here and is this going to be a Turd that will not polish...upon stripping it I discovered everything was a little tight and burs all over the place so I grabbed the dremel scotch bright and polishing kit and went to town on the reciever bolt/carrier group feed ramp ETC...You could see just from hand cycling where things were touching and some of that is okay but this was excessive..It took me a little while to get it the way I wanted but when finished upon putting it all back together it was a different rifle action was smooth and at the range it would cycle every load I threw at it...I did not have to take off alot of material or anything but there were a bunch of high spots....Hope this helps </div></div>

Did you have burrs on the interior of the upper receiver that were scoring the bolt carrier? Where did you find these defects? Thanks!

Yes there were imperfections in both the reciever and bolt/carrier group it was not a huge deal just had to blend everything...I did not shoot the rifle before it was worked on so I can't say how it would have run but it was stiff as hell prior to my modification...I wish I had taken some pics before selling it but a friend of mine bought a 5.56 DPMS rifle and brought it to me for inspection and it did not have any of the issues I described...
</div></div>

 

[Mr.Maim]

Re: Troubleshooting Failure to Feed on a DPMS LR-308

Hmm interesting Cramey74. I'll take a look. Thanks!

 

[cramey74]

Re: Troubleshooting Failure to Feed on a DPMS LR-308

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Mr.Maim</div><div class="ubbcode-body">Hmm interesting Cramey74. I'll take a look. Thanks! </div></div>

Man I'm telling you if yours is as bad as mine was you would know it!!! I got mine in a trade I believe it was the LR308T it did not have a forward assist 16" barrel A2 stock and flash hider I just chalked it up to it being one of their entry level weapons..A friend had a .308 SASS at the same time and it was a lights out shooter and never had one problem..Sorry your having problems that SUCKS!!!

 

[Casey Simpson]

Re: Troubleshooting Failure to Feed on a DPMS LR-308


Maim, get Zediker's books on AR's.

Let Derrick Martin at Accuracy Speaks fix your rifle. He can.

 

[.308ing]

Re: Troubleshooting Failure to Feed on a DPMS LR-308

Made it out to Ben Avery today. With 120 rounds varying from Remington soft tip to Hornady Tap.

Rifle worked flawlessly for the first 40 round firing cheap Federal and Remington ammo. The gunsmith said he fired 100 rounds of Remington with out problems.

Hornady was another story. 155 grn a-max failed to feed and a friend told me that the casings were limping out of the ejection port. I thought it may have been a dirty rifle issue but noticed one of Hornady casings was missing the primer. Now I am wondering if it may have been an ammo / timing issue.

I am going to call DPMS and see what they can tell me.

By they way, my gunsmith report was in cursive but in black ink.

 

[Casey Simpson]

Re: Troubleshooting Failure to Feed on a DPMS LR-308


These ARs must be lubed properly, but if they have been, they shouldn't be failing.

 

[.308ing]

Re: Troubleshooting Failure to Feed on a DPMS LR-308

While cleaning the rifle I noticed that the gas block was loose. I think this may have been contributing to my problems all along. I will apply some Red loc tite and report back.

 

[T383]

Re: Troubleshooting Failure to Feed on a DPMS LR-308

Mr.Maim, have you got it fixed yet. If so, what was the cause.

 

[MontanaHick]

Re: Troubleshooting Failure to Feed on a DPMS LR-308

Mr.Maim,
How is this progressing for you? Are you still getting those marks on your brass (especially the dimple below the shoulder)? I've got a DPMS SASS rifle juuuust about paid off and I'm crapping myself reading this thread. I DON'T need to waste $2k on a rifle that's gonna make me want to test it with their 'smiths as targets...

 

[hlee]

Re: Troubleshooting Failure to Feed on a DPMS LR-308

@ MontanaHick... My LR 308 (heavy 24" bull barrel) goes bang every time I squeeze the trigger, feeds flawlessly from pmags and dpms steel mags, and shoots sub moa on the rare occasions when I do my part. Mine has a PRS stock and a JP adjustable gas block. Don't sweat the problems that other people are having unless you are having them too. The people not having problems (majority) are not posting, they are shooting...

 

[MontanaHick]

Re: Troubleshooting Failure to Feed on a DPMS LR-308

@hlee- I'm hoping this holds true. I tend to have good luck with my rifles and their functioning, but his *looks* like the same SASS build I'm purchasing (although the OP mentioned it came with some additional parts). I'm also told by several ex-army guys turned AR-smith that the DPMS rifles are particularly susceptible to malfunction when one begins swapping parts, especially non-DPMS parts, so I'll be avoiding that...

@Mr.Maim- how are things, sir, with your rifle? I'm hoping for the best.

 

[Mr.Maim]

Re: Troubleshooting Failure to Feed on a DPMS LR-308

Sorry for the delayed response. Business is good and I've been busy.

The rifle is a finicky, picky bitch that works when it wants to. It'll FTE and FTF on any ammo with any magazine, with any level of cleanliness, with any buffer/spring/stock, gas tube, bolt, carrier, extracter, etc., etc., etc., I've had more than enough with dealing with it and DPMS's deplorable customer service and asshat gunsmiths who can't be bothered to come to the phone or document their NON work.

Rifle is in the back of the safe and will get sold when I have the time, or give a shit more about it.

If your DPMS works, great, congratulations. If it doesn't, good fucking luck with warranty support.


That being said: I'm not taking any more suggestions on troubleshooting. I apprecaite the effort from you guys, I really do, everyone has been really great and outgoing... but I have better things to do with my time and money to be repeatedly disappointed with this 12-pound boat-anchor rifle. I'm currently finishing up a semi-custom FNH bolt rifle and will be placing an order for a DTA SRS in the spring to fill my semi-auto desires.

I hope this thread proves helpful to other members.

Over it and done.

Fuck DPMS.

 

[Augustus]

Re: Troubleshooting Failure to Feed on a DPMS LR-308

I know this thread is a little old and sounds like Mr Maim is sick of the DPMS. I had a similar experience with an LR 308. Just like Mr Maim I screwed with it until I got sick of it and put away.

I got around to messing with it again and out of frustration I drilled the gas port out to 7/64, presto, the rifle is running flawlessly.

Ejection is at 2 o'clock about 4 ft away, prior to drilling it would fail to eject, slam on the empty case or fail to feed. I think the rifle was under gassed.

Anyway I may have voided the warranty but I dont care, it works now.

 

[Txhillbilly]

Re: Troubleshooting Failure to Feed on a DPMS LR-308

I recently bought a new DPMS LR-260H and it also had problems with rounds getting jammed half-way into the chamber,and also wouldn't lock the bolt open after the last round.

The buffer spring seems to be far too heavy in this weapon,and short cycled the BCG.If I manually pull the bolt back,it locks back fine,but it won't lock back when fired.
I installed an ACE skeleton buttstock on it before it was ever fired,and I cut down the supplied bolt because it was too long.
I contacted DPMS,and that was the first thing they said was the problem-WRONG. I asked them if they offered a lighter weight buffer spring and they said no,that was the correct spring for the weapon,I said it is too stiff.

I fired up my air compressor,and with a cutoff wheel started cutting off 1 coil of the spring at a time,and then test firing the weapon. I ended up cutting off 3 coils from the spring before the BCG would lock back after firing.
That solved both the failure to lock back the BCG,and the Jamming problem on this rifle.

The chamber lugs on this rifle also had very sharp/rough edges that were really marking up my brass and bullets,and the very 1st shot from any magazine would be low and to the right.
I took some sandpaper and emory cloth,and smoothed out all the rough/sharp edges in the chamber lugs,and that solved those issues.
I'm using the factory mags,as well as P-mags,and a 10rd Stoner mag.They all seem to function well with this rifle.

Now,if I can just find the right bullet for this thing.
It shoots 140gr Sierra GameKings pretty good,but hates the Hornady 140gr SST's.I have some Speer 140gr,but haven't had time to work up any test loads yet.

Now that I have the gun functioning well,I can get back to testing it more.

 

[Augustus]

Re: Troubleshooting Failure to Feed on a DPMS LR-308

I thought about cutting the buffer spring down but I was afraid it would not have enough strength to chamber effectively. Opening up the gas port worked on this particular rifle.

DPMS Seems to have a problem with the LR series, it appears to be in the spring, gas port or a combination of both.

The good news is it appears to be fixable.

 

[Txhillbilly]

Re: Troubleshooting Failure to Feed on a DPMS LR-308

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Augustus</div><div class="ubbcode-body">I thought about cutting the buffer spring down but I was afraid it would not have enough strength to chamber effectively. Opening up the gas port worked on this particular rifle.

DPMS Seems to have a problem with the LR series, it appears to be in the spring, gas port or a combination of both.

The good news is it appears to be fixable.
</div></div>

Since I shoot left handed,I'm able to see the BCG operate when fired,and it was operating fine with the gas pressure.The spring was just too heavy to be completely pushed back.
I laughed at the DPMS tech when I called him back after cutting the spring,and letting him know that they don't know it all!

I had the same problem with my 458 SOCOM,and that's what fixed it also.

 

[Jim/Woods3ofus@inwvheaven]

Re: Troubleshooting Failure to Feed on a DPMS LR-308B

Does this happen when you cycle the action with the charging handle? Or does it also happen when the action cycles after firing?

I just asked these questions. I have the AR10 LR308 and I can manually load the first round and fire it. The problem was no ejection and obviously no loading a second round. Side not: dust cover was closed after first round chambered and was open after the round was fired. Can you provide a solution?

 

[hlee]

I just asked these questions. I have the AR10 LR308 and I can manually load the first round and fire it. The problem was no ejection and obviously no loading a second round. Side not: dust cover was closed after first round chambered and was open after the round was fired. Can you provide a solution?

Wow, how did you find this 9 year old thread?

Anyway, what ammunition- specifically?
Is this a rifle that you or someone else built? Is it a factory built gun?
Is this gun new, or is this something that just started?
Is the BCG lubricated? Doesn't need to be sloppy wet, but should at least glisten with oil.
DPMS chambers have been said to be somewhat rough, and benefit from a mild polishing. I put some rubbing compound on a chamber mop, chucked it into a cordless drill, and went to town on mine. Other than that, it sounds like it is short stroking- the bolt moved enough to open the dust cover, but not far enough to extract or load.

Likely culprits are insufficient lubrication, heavy buffer, heavy spring, insufficient gas from the gas block, and underpowered ammunition.

 

[Jim/Woods3ofus@inwvheaven]

Wow, how did you find this 9 year old thread?

Anyway, what ammunition- specifically?
Is this a rifle that you or someone else built? Is it a factory built gun?
Is this gun new, or is this something that just started?
Is the BCG lubricated? Doesn't need to be sloppy wet, but should at least glisten with oil.
DPMS chambers have been said to be somewhat rough, and benefit from a mild polishing. I put some rubbing compound on a chamber mop, chucked it into a cordless drill, and went to town on mine. Other than that, it sounds like it is short stroking- the bolt moved enough to open the dust cover, but not far enough to extract or load.

Likely culprits are insufficient lubrication, heavy buffer, heavy spring, insufficient gas from the gas block, and underpowered ammunition.

 

[Jim/Woods3ofus@inwvheaven]

Before I became a member, which was a few minutes ago, I was researching this problem. This thread was one of the first ten or so repair suggestions that came up. I bought the gun new about year or two ago. The first 10 rounds or so were intermintantly. Now it is everytime. i am using new in the box .308 168 grain shells. It is a factory, out of the box. Clean and lubbed big time.( I am a retired Army Sergeant). I have cleaned and lubbed Ar's a few times, this one is what I call excessive. I will start with the Buffer and buffer spring. What brand would you suggest? I took my rifle apart, My buffer is approx. 2 and 7/16 inches long, the spring is approx. 11 inches long. Is that anything close to what it should be in length?

 

[hlee]

Before I became a member, which was a few minutes ago, I was researching this problem. This thread was one of the first ten or so repair suggestions that came up. I bought the gun new about year or two ago. The first 10 rounds or so were intermintantly. Now it is everytime. i am using new in the box .308 168 grain shells. It is a factory, out of the box. Clean and lubbed big time.( I am a retired Army Sergeant). I have cleaned and lubbed Ar's a few times, this one is what I call excessive. I will start with the Buffer and buffer spring. What brand would you suggest?

If you are a money is no object kind of guy, get the JP Silent Capture Spring builders' kit for the AR10 platform. That gives you a choice of spring weights, and you can also mix and match the weights (sold separately) in the buffer to get reliable functioning.