DPMS 5.56 .223 buffer spring question

Ghost In The Fog

Ghost In The Fog

Member
Joined
Oct 21, 2015
Messages
253
Location
Colorado
Hey everyone.
Help please.
Factory stock DPMS Oracle 5.56 will not cycle/eject
I have approximately 2,000 rounds through with ZERO issues. cleaned frequently, every 300-500 rounds.
At the range yesterday, I set up 10 water bottles and the first 6 were dead on. #7 jammed-double feed. Cleared the jam and then it would not eject or cycle. I noticed on the previous range trip that the charging handle would not feed the first round to battery after inserting the magazine and I had to use the bolt release.
I cleaned it toughly. BCG completely taken down. Ejector and extractor both are good. Everything is in good shape nothing broken or excessively dirty. Took it to the range this morning and brought along a BCG from another rifle. Neither would eject the fired round.
I am by far no expert, that is why I am asking here. This led me to buffer and spring. The whole assembly looks like it is new. Spring is lightly oiled and in good shape.
I looked online, and apparently, DPMS no longer has customer service? But found that the carbine buffer spring should be 10.5" long and have 37 to 39 coils. I have 38 coils and it measures 10-7/8" In my past experience, the buffer spring shrinks as it wears.
Could a worn buffer spring cause this? Even though it is as long or longer than new?
I do keep this rifle with the magazine in and bolt carrier locked back.
It is my understanding and information from spring manufacturers that keeping magazines loaded to full capacity and bolt locked back will not cause wear.
i really don't know what else to think. Next step I guess would be a gunsmith.
Any recommendations for a stock replacement spring would be much appreciated. There are so many choices, and I am hoping for a good, reliable replacement.
Thank you for reading.
 
@MistWolf - he knows more than I do about ARs

An AR will cycle and eject a round, even if there is a problem with the buffer spring, it just won't feed very well. Is sounds more like something happened with the gas block/ front sight alignment or the gas tube.

What ammunition are you using?
 
Last edited:
MarshallDodge said:
@MistWolf - he knows more than I do about ARs
An AR will cycle and eject a round, even if there is a problem with the buffer spring, it just won't feed very well. Is sounds more like something happened with the gas block/ front sight alignment or the gas tube.
What ammunition are you using?
Click to expand...

Winchester 223 55 grain
Frontier 556 55 grain
Tula 223 55 grain (Steel case)
Hornady VMax hand loads
All have worked flawlessly previously. Frontier, Tula and VMax were tried on Sunday and only the Frontier and Tula this morning.
Would a problem with the gas block/front sight alignment cause a round not to chamber all the way when using the charging handle? Maybe a combination of things? I'm so confused and grateful for your reply.
 
MarshallDodge said:
Does the gas key in the bolt carrier look like it is interfacing correctly with the gas tube?
Click to expand...
I removed the glacier guards, everything seems to be tight and straight. I can't really see the point of connection through the ejection port or from the bottom. It appears to fit but I can't really tell for sure.
I did take a can of compressed air and stuck the air tube into the gas tube where the bolt carrier meets the tube and air only blew back towards the rear of the gun. I don't think this is scientific, but shouldn't I feel it coming out the front? Could the gas tube be blocked? If so, is there a way to check without removing everything? I just called my LGS and they are backed up 5 to 6 weeks.
I have not dropped or banged the gun.
Thank you for your help.
 
Ghost In The Fog said:
I noticed on the previous range trip that the charging handle would not feed the first round to battery after inserting the magazine and I had to use the bolt release.
Click to expand...

The CH is not pulling the BCG back far enough to disengage the bolt catch?
Sounds like a separate issue from not ejecting, possible worn CH..

You've ruled out the BCG.
That gas block would be where I would start.
It should have just two set screws in the bottom, the barrel is most likely not dimpled for a set screw and being exposed is prone to getting knocked about. I wouldn't trust a dimple to hold it either, for an exposed gas block pinned is best.
You should hear air escaping from the front if you are shooting air in the back of the gas tube.
If not then you'll have to go deeper.

May be a good time to upgrade a couple of things if the gas block is coming off.
It always turns into that for me anyway.
 
@MarshallDodge Interesting thing happened. As I was further checking how the gas block was attached, I discovered the two hex screws were lose and the gas block was able to slide back and forth about 3/16th of an inch. I think this would explain why the bolt remained closed after firing a round if there was not a complete seal between the gas tube and key.
I have only assembled lowers and know very little about uppers but I am learning. Thank you for your replies. It helped figure this out. Or at least I think this has to be it. I will post results after my next range trip so maybe it can help someone else down the road.
Thank you.
 
Try blocking the barrel at the breach end with a tight cleaning patch, and blowing air in the breach end of the gas tube while putting your hand at the muzzle end of the barrel. If you don't feel anything then the gas block probably moved out of alignment with the port.

On edit: Glad you figured it out :)
 
Another area to look at is the gas rings on the bolt. If the gun was working properly before, it could be the gas block, and it could also be the gas rings. They are inexpensive and may deserve to be replaced.
 
Ghost In The Fog said:
As I was further checking how the gas block was attached, I discovered the two hex screws were lose and the gas block was able to slide back and forth about 3/16th of an inch. I think this would explain why the bolt remained closed after firing a round if there was not a complete seal between the gas tube and key.
Click to expand...
The gas block moved and blocked off the gas port in the barrel, it doesn't take much to shut it down.
Which is why it's a good idea to at least dimple the barrel and give it a fighting chance to stay put, or pin it.
 
Ghost In The Fog said:
@MarshallDodge Interesting thing happened. As I was further checking how the gas block was attached, I discovered the two hex screws were lose and the gas block was able to slide back and forth about 3/16th of an inch.
Click to expand...

Just FYI...

I have an Oracle. I pumped about 1000rds through it over a weekend a few years ago, decided it was reliable enough, if not necessarily super accurate, and then gave it to my brother for his birthday. This past year, I built him a new upper... after shooting it for 2 years, he had worked out what he wanted, and didn't want, so I built him the upper he wanted. I brought back the Oracle upper, and decided to take it apart... just for fun. While the gas block was tight... same 2 Allen head screws you have... the barrel nut was on hand tight... which explained the sub-par accuracy I saw with it. I thought it was just a chezzy barrel, but in fact, the barrel nut wasn't even torqued. So... these days, even if I am handed a brand new AR... I tear it apart to make sure it's assembled correctly.

Oracle on the right... reassembled... correctly! I stuck it on a PSA lower I assembled from parts. It's my spare to my spare AR... as one is none, and two is one... I just figured 3 is 2.

JJqmtcbl.jpg
 
As an aside... I just went through the whole cycling/troubleshooting issue with my main AR... (the LRB in the center, photo above.) After about 5000 rounds, it started stovepiping and being stupid. I thought it was something in the gas system, or, at the outside, the bolt or carrier... but after swapping a bunch of parts around, it wound up being the buffer and spring.

I replace the action spring with a standard (white) Springco spring, and an H1 buffer, and I'm back in business. I'm a rabid spring changer on my semi-auto pistols... I don't know why I ignored the springs on my AR.

Documented here...

https://www.thehighroad.org/index.php?threads/do-ar-gas-rings-wear.916850/
 
I appreciate everyone's help.
I will keep this short for now and will follow up after more rounds through.
The gas block set screws came lose and the block did move and disconnect from the gas tube. I aligned and slid everything back into place and tightened the set screws. The gas block is not pinned, and I will be looking into replacing the set screws with what @powermad suggested to keep it from happening again in the future and checking these screws will now be part of routine maintenance.
I took it to the range, and it works like new. A few slow fire rounds and then the obligatory mag dump. LOL. This has been a fantastic rifle and it is my go to. Even though I have plenty of other options, it is surprising to me just how upsetting it was not to have this rifle in service.
Thank you for helping and all the suggestions. I really appreciate it.
Brad
 
Ghost In The Fog said:
Fantastic thread. Thanks for sharing.
Click to expand...

Like you, I had what was previously a 100% reliable rifle, just all of a sudden go belly up. It wound up being something simple, just not what I thought it would be. ;) The whole process to troubleshoot the problem has led me to a better understanding of what makes an AR work, and, by default, what can go wrong.

FWIW, I'm not opposed to screw down gas blocks, but they do require some attention to make sure they are secure and working right. The gas block on the Oracle seems to be pretty robust, to include the hex screws securing it in place; I have no plans to change mine, and if I ever decide to change the barrel to a middy gas, I'll prolly just keep the block and put a new gas tube on it.
 
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