# Need help with dpms 308



## Drow (Feb 10, 2009)

I just bought a dpms sportical 308 from a guy that was advertised as brand new never fired. So I put a scope on it and head to the range to get it sighted in. On the first shot the rifle fired like it should but it did not kick the shell out. So I grab the slide deal and manually kick the shell out. Mind you when pulling the slid deal back, it was pretty dang hard! Load another shell in and same thing. This happened with 3 different brands of ammo at various grains. I probably shot it about 10 times with the same results. The bolt would make ZERO attempt to kick the shell out. Basically after the shot the AR turned into a bolt gun with me having to manually kick the shell out. Anyone have any thoughts on this? I did take it to a local gun shop and the guy behind the counter looked it over and said there were no adjustments to be made to the gas system on this particular AR and I'd have to try and send it back into DPMS. 

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## dwilliams35 (Oct 8, 2006)

May have an issue with the gas system either being clogged, damaged, or incorrectly adjusted. Beyond that, thereâ€™s about a billion things that could be going wrong in the receiver or stock.


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## muney pit (Mar 24, 2014)

Sounds like the gas block is not centered over the gas hole on the barrel. Ive seen this 2x on other ar's. If its the set screw type of gas block its as simple as loosening the set screws. Using a piece of wire to line the hole from the barrel side and retighten. If its a taper pin style then its gotta be redrilled. And if its new like yours id send it back to dpms. But the other type is usually a 5 min fix.

These troubleshooting things can be 1in a million things but just make sure the bolt rides free, isnt hanging up on anything. And if ya dont see anything that pops out at ya just send it back to dpms


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## DIHLON (Nov 15, 2009)

muney pit said:


> Sounds like the gas block is not centered over the gas hole on the barrel. Ive seen this 2x on other ar's. If its the set screw type of gas block its as simple as loosening the set screws. Using a piece of wire to line the hole from the barrel side and retighten. If its a taper pin style then its gotta be redrilled. And if its new like yours id send it back to dpms. But the other type is usually a 5 min fix.
> 
> These troubleshooting things can be 1in a million things but just make sure the bolt rides free, isnt hanging up on anything. And if ya dont see anything that pops out at ya just send it back to dpms


You should be able to measure the distance of the hole in the gas block and barrel and get it close enough. The hole in the gas block is typically larger than the one on the barrel, so it does not have to be exact.


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## Bird (May 10, 2005)

I agree with muney pit about the gas block misalignment. See if you can run some heavy leader through the gas tube to make sure it is clear up to the gas block. If you take a pipe cleaner and run it in the gas tube from the upper receiver and there isnâ€™t any carbon or soot residue, you arenâ€™t getting any gas to blowback the bolt carrier. Maybe the gas key isnâ€™t engaging the gas tube. This would also be an issue if the gas block isnâ€™t aligned properly over the gas port. If you arenâ€™t AR platform rifle savvy, take it to a good gun store/gunsmith. None of it is difficult to do but you might need some special tools depending on how much you will need to disassemble.


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## RandyM (Jul 14, 2005)

muney pit said:


> Sounds like the gas block is not centered over the gas hole on the barrel. Ive seen this 2x on other ar's. If its the set screw type of gas block its as simple as loosening the set screws. Using a piece of wire to line the hole from the barrel side and retighten. If its a taper pin style then its gotta be redrilled. And if its new like yours id send it back to dpms. But the other type is usually a 5 min fix.
> 
> These troubleshooting things can be 1in a million things but just make sure the bolt rides free, isnt hanging up on anything. And if ya dont see anything that pops out at ya just send it back to dpms


This has happened to me, the front gas block was out of alignment,


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## dwilliams35 (Oct 8, 2006)

One thing wrong with this, I started with the gas block theory too, but that wouldnâ€™t make the charging handle and bolt carrier hard to pull back... thatâ€™s subjective, of course, but there may be another problem.


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## RandyM (Jul 14, 2005)

actually it did with mine, its a gas operated system, it uses the gas to push the bolt open, if you are not getting the right amount of gas pressure, the bolt does not have enough power to extract the case.
I almost had to beat the spent round out. 
When I removed the gas block from the barrel, you could see a half circle powder burn on the barrel next to the gas port on the barrel, where the gas block port, and port on the barrel had not lined up correctly.


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## Drow (Feb 10, 2009)

dwilliams35 said:


> One thing wrong with this, I started with the gas block theory too, but that wouldnâ€™t make the charging handle and bolt carrier hard to pull back... thatâ€™s subjective, of course, but there may be another problem.


Ya man that was one thing that was kind of bothering me about it as well. When I say it's hard to pull back after the shot, I'm not talking about like I have to pull and hit the stock on the ground or anything. I'm taking about having to pull it pretty dang hard with 2 fingers to get it back.

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## Drow (Feb 10, 2009)

And thanks for all the replys y'all. I'm new to the ar world so I don't really know much about them at all. I'm going to tear into it as soon as I have some time and go from there. 

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## DIHLON (Nov 15, 2009)

D~Row said:


> Ya man that was one thing that was kind of bothering me about it as well. When I say it's hard to pull back after the shot, I'm not talking about like I have to pull and hit the stock on the ground or anything. I'm taking about having to pull it pretty dang hard with 2 fingers to get it back.
> 
> Sent from my SAMSUNG-SM-G930A using Tapatalk


Unlike a bolt gun, the AR has a spring that is opposing the handle as you pull it back to charge/discharge a round. Compared to a bolt gun, yes it is significantly harder to pull back due to this opposing force.


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## Wado (May 15, 2011)

Action may be a little on the dry side. Might need some frog oil along with the repairs everyone seems to agree on.


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## Chase4556 (Aug 26, 2008)

For sure check your gas block alignment. Odds are, this is the issue. If it feels like nothing is hanging up when you cycle the action by hand, and it wont extract the case, I'd put money its probably the gas block. 

The action may feel a little tight or gritty when you operate it by hand, most ARs are and after they shoot and break in it will get smoother. 

As far as the brass being difficult to remove, when you shoot the case expands and that extra force and friction in your chamber can make it difficult to remove I'm sure. If it were a case being stuck issue, I'd think you would have broken case heads where the extractor ripped off after trying to extract. Seems like you are not getting anything, so again back to gas block.


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## dwilliams35 (Oct 8, 2006)

D~Row said:


> Ya man that was one thing that was kind of bothering me about it as well. When I say it's hard to pull back after the shot, I'm not talking about like I have to pull and hit the stock on the ground or anything. I'm taking about having to pull it pretty dang hard with 2 fingers to get it back.
> 
> Sent from my SAMSUNG-SM-G930A using Tapatalk


Whatâ€™s the odds you have a scale that could tell you exactly what youâ€™re talking about there? Mines harder than a standard small frame AR, but heck, itâ€™s going to be..


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## sea sick (Feb 9, 2006)

The blowback pushes directly onto the bolt its self, which cannot get unlocked because of the corresponding lugs behind it. The gas will than enter the carrier and pull out the bolt. Noticed the shape of the cutout on the carrier for the bolt cam pin, which allows the bolt to rotate out of the way only when pulled out by the carrier.Â 
Reason it's hard to pull back is the lugs are still engaged and you have to rotate manually when pulling BCG to the rear.

Guna go with incorrect gas tube alignment....but hey, I've been wrong before. Good luck...hate to hear it.


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## mley1 (Feb 22, 2009)

Did you clean it before firing it? Also, how was it loobed? On new AR styled rifles I always clean it real good, including blowing out the gas tube with gun scrubber to make sure it's all clear and lined up with the gas block. Then I lube the BCG pretty heavy with Mobil 1 5w20 oil. I've found that my .308 AR likes to be run wet. In fact, I run all my AR's wet.


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## THA (Jan 5, 2016)

Picked up a new upper for mine and after got home, the bolt was very tight to pull back charging handle. Had to really pull hard on charging handle and even bump it with my hand. Tried to fire a round and it stuck. Disassembled the bolt and caming surface was hard to rotate. thoroughly cleaned it and rubbed it with steel wool and it eased up after playing with it a while and oiling it it eased up and now functions like it should.

Take your bolt apart and try to rotate locking through the cam rotation. If that is tight, that is probably your problem


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