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12/17/2015 3:27:50 AM EDT
I have a fairly new Daniel Defense Ambush 556. Its a very accurate rifle. The problem is the about every 3 to 5 round it will not chamber. The shell sits on top of the extractor instead of seating fully into the bolt face. This results into the shell slamming into the side of the chamber causing a jam. I have tried Pmags, promags and usgi mags. No change. I have also tried several different brands of ammo, still no change. Probably have around 700 rounds through the rifle. Any thoughts or ideas would be greatly appreciated.

Thanks Bobby
12/17/2015 4:01:35 AM EDT
[#1]
Picture of the bolt face?

Does the extractor have a spring or spring and o-ring? If o-ring, try just running the spring.
12/17/2015 4:35:54 AM EDT
[#2]
it does have and o ring. and is extremely stiff. the extractors moves a lot easier without the o ring. also the rubber piece inside the spring has no head on it at all. I will try without the oring as soon as possible. I would post pics but I cant figure out how.  
thanks for the help
12/17/2015 6:02:35 AM EDT
[#3]
could it be an ejector issue? the ejector sits flush with the locking lugs and has a very sharp edge. I wonder if it is keeping the shell from moving over far enough to sit in the bolt face?
12/17/2015 7:26:40 AM EDT
[#4]
Quoted:
This results into the shell slamming into the side of the chamber causing a jam.
View Quote


You lost me here,
is the tip of the round missing the chamber on feeding all together, such a low feed out of the mag into the upper receiver from surface before the feed ramps, or the round never making it out of the mag to begin with?

If so, a photo would help to see what kind of jam you are having.
12/18/2015 1:51:59 AM EDT
[#5]
The cartridge starts into chamber. About half way in the side hits the camber hard enough to gouge the brass. As I said the round won't move off the extractor far enough to seat into the bolt face. I can't figure out to post pics

12/18/2015 12:04:23 PM EDT
[#6]
To post a photo on the site, you need to first host them to something like Photo bucket, then post the link from the photo on the host site to here.
12/18/2015 6:38:29 PM EDT
[#7]
Gotcha thanks dano
12/18/2015 7:02:12 PM EDT
[#8]
Quote History
Quoted:
Picture of the bolt face?

Does the extractor have a spring or spring and o-ring? If o-ring, try just running the spring.
View Quote


This worked for me, my current rifle has an oring and cycles just fine. My last one had the issue you described, ditching that oring fixed it. It's worth a try , only takes a minute to test fire with and without it.
12/19/2015 11:50:55 AM EDT
[#9]
It could be numerous things.
O ring on extractor.



New rifle very stiff bolt.



Extension spring too weak.



Carrier rubbing or sticking.



Bolt binding.



Mag rubbing on bolt carrier slowing it down.



Bad mag.



Gas tube hitting key.



Bad barrel extension.

Bad carrier.

Bad bolt.



Look for simplest easiest first. Try swapping mag and BCG with a known working rifle.
I would remove O ring and use a tubbs flatwire spring. You could also add a heavier buffer.
Is your brass landing at 3:30?






 
12/19/2015 2:17:59 PM EDT
[#10]
Looking at the face of the bolt, only the ramped portion of the front of the ejector should be protruding into the recess. Sometimes the ejector protrudes too far allowing the flat area beyond the ramp to butt up against the case, which will cause your issue.
12/19/2015 8:14:52 PM EDT
[#11]
Contact DD.  send it in to them and have it fixed.
12/19/2015 11:05:28 PM EDT
[#12]

Quote History
Quoted:


Looking at the face of the bolt, only the ramped portion of the front of the ejector should be protruding into the recess. Sometimes the ejector protrudes too far allowing the flat area beyond the ramp to butt up against the case, which will cause your issue.
View Quote
I have also seen extractors that were not machined properly. There was no way for the case rim to ramp down the extractor and go under it.



 
12/20/2015 9:22:35 AM EDT
[#13]
Thanks everyone for the suggestions. I'm gonna go through all of them over Christmas break. The brass come out at about 3 o'clock and flies a good 20 ft easily
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