New 14.5 Build, Failure to Extract Issues [Archive]

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j200pruf

02-13-12, 18:23

Hey all, I took my M4 build out for the 3rd time and am still having issues with Failure to Extract (I have various pics below showing the issues). Upper is a DS Arms (thinking this was a huge mistake now) 14.5" 1:7 Chrome Lined 5.56 with a long enough flash hider pinned and welded on. I am running a standard carbine spring with a Spikes ST-T2 Buffer. LMT Full auto BCG, it does have the correct spring, black rubber insert, and o-ring.

So far I have tried a bunch of ammo (Old Norinco .223 I had, American Eagle .223, Lake City 55gn 5.56 ball, American Eagle 55gn 5.56ball, and some Hotshot 62gn 5.56 brass cased berdan primed). The biggest issues are the Hotshot and old Norinco. I didn't get any issues with the Lake City or American Eagle .223 (but I was only loading 1 or 2 rounds per mag).

The first 2 times I took this carbine out I don't think I cleaned it properly. I was having problems with rounds not being extracted from the chamber. Some of them would be very hard to remove by manually charging the rifle(I would have to apply pressure to the charging handle and bump the stock on the ground). Before I went out yesterday I cleaned the hell out of the upper. It did seem to help a little bit, but I still had a hell of a lot Failures to Extract, and a couple Failures to Eject. Any rounds that failed to extract were very easily removed by manually charging the rifle, and a few rounds would simply drop out of the chamber when I locked the bolt back. Per a troubleshooting tip I tried loading all of this ammo 1 round at a time per mag. There was enough pressure to lock the bolt back on every single shot, even with the crappiest ammo I had brought out.

I also noticed that all of the rounds had marks on the rims, and near the end of the day I was noticing little pieces of brass in the upper, so it looks like the extractor is working pretty well. I kept all of the brass that had problems and will try and put some good pics up tonight or tomorrow.

Other than sending the upper to DS Arms is there anything else I can try? Maybe a heavier buffer spring/buffer?

Why didn't I just spend a bit more and go with BCM :suicide: At least I got it to put rounds on target (shooting 1 round at a time was a bit of a PITA though).

Here are some pics of the weekend
http://i441.photobucket.com/albums/qq134/j200pruf/AR%20Stuff/FtE11_2-12-12.jpg
http://i441.photobucket.com/albums/qq134/j200pruf/AR%20Stuff/FtE10_2-12-12.jpg
http://i441.photobucket.com/albums/qq134/j200pruf/AR%20Stuff/FtE09_2-12-12.jpg
http://i441.photobucket.com/albums/qq134/j200pruf/AR%20Stuff/FtE08_2-12-12.jpg
http://i441.photobucket.com/albums/qq134/j200pruf/AR%20Stuff/FtE07_2-12-12.jpg
http://i441.photobucket.com/albums/qq134/j200pruf/AR%20Stuff/FtE06_2-12-12.jpg
http://i441.photobucket.com/albums/qq134/j200pruf/AR%20Stuff/FtE05_2-12-12.jpg
http://i441.photobucket.com/albums/qq134/j200pruf/AR%20Stuff/FtE04_2-12-12.jpg
http://i441.photobucket.com/albums/qq134/j200pruf/AR%20Stuff/FtE03_2-12-12.jpg
http://i441.photobucket.com/albums/qq134/j200pruf/AR%20Stuff/FtE02_2-12-12.jpg
http://i441.photobucket.com/albums/qq134/j200pruf/AR%20Stuff/FtE01_2-12-12.jpg
http://i441.photobucket.com/albums/qq134/j200pruf/AR%20Stuff/FtE12_2-12-12.jpg

ViperRy

02-13-12, 18:38

Have you checked the headspace?

j200pruf

02-13-12, 18:51

I haven't checked head space, but the bolt does freely close on any .223 or 5.56 ammo I have put in the chamber with the ejector removed.
Would I want to check with a field gauge, or a go gauge?

JusticeM4

02-13-12, 19:52

My thought is that its ammo related or possible your firing pin.

If its firing all the American eagle ammo (this is what I use with no issues) and not the other ammo, that can be the problem. I'm not 100% positive, but if one brand of ammo works and not another, that could be the problem.

Bimmer

02-13-12, 23:47

The biggest issues are the Hotshot and old Norinco. I didn't get any issues with the Lake City or American Eagle .223 (but I was only loading 1 or 2 rounds per mag).

Here's your answer.

Stop using crappy ammo.

Iraqgunz

02-14-12, 00:33

I believe that the issue here is (once again) a tight chamber. I also think you need to take that O-ring off as well. In some cases you can have too much extractor tension and this will cause all kinds of issues.

You need to get someone with an M-guns chamber checker to check it and I would go so far as to say that I would ream it. I am pretty sure that this is going to solve the problem. Due to the cost of the checker and reamer your only real option is to simply replace the barrel.

polymorpheous

02-14-12, 03:11

Tight chamber as IG stated.
Sell the upper and use the funds to buy a quality upper.
Lesson learned, I did the same thing with my 1st AR.

WS6

02-14-12, 06:01

Chamber dimensions are poor, or steel-cased ammunition or the like has allowed for a fouled chamber that has not been cleaned.

Travis B

02-14-12, 08:09

Ditch that shitty ammo and try again. If it's still doing it then it's a chamber issue.

Dave L.

02-14-12, 08:19

I believe that the issue here is (once again) a tight chamber.

Agreed. That was my first thought.

OP, find someone with Ned Christiansen's chamber reamer and have it done.

jonconsiglio

02-14-12, 11:38

Not suggesting anything here since I haven't handled the rifle myself, but have you run it with a heavier buffer? What buffer are you currently using?

Just like the other thread, this may very well be a tight chamber.

j200pruf

02-14-12, 14:14

ST-T2 Buffer

Thanks all, I saw some chatter marks in the chamber. I mentioned this to one of the DS A gunsmiths, they are just going to replace the barrel.

Iraqgunz

02-14-12, 23:11

Good luck. After you get tired of dicking around with their stuff, get a real barrel.

ST-T2 Buffer

Thanks all, I saw some chatter marks in the chamber. I mentioned this to one of the DS A gunsmiths, they are just going to replace the barrel.

WS6

02-15-12, 00:03

ST-T2 Buffer

Thanks all, I saw some chatter marks in the chamber. I mentioned this to one of the DS A gunsmiths, they are just going to replace the barrel.

Have them replace it, then sell it as new to someone who will buy it (as it will be new), and purchase a replacement of good quality.

careboy

02-16-12, 01:17

Just like the other thread, this may very well be a tight chamber.
http://www.primeaffiliate.com/track/images/22.gif
http://www.canadablackberry.com/imgs/images/2.tod.gif

WS6

02-16-12, 01:42

Just like the other thread, this may very well be a tight chamber.
http://www.primeaffiliate.com/track/images/22.gif
http://www.canadablackberry.com/imgs/images/2.tod.gif

Chatter marks in chamber, several posts up. Shitty barrel is shitty.

digdug18

02-16-12, 11:47

Chatter marks aren't the barrels fault, most likely the person that cut the chamber didn't bother to blow out the chips or didn't use enough cutting fluid for a smooth cut.

I'm thinking you could polish the chamber and you wouldn't have a problem, though this might be a PITA.

Tweak

02-16-12, 20:53

How badly offset is the extractor groove of the fired case?

does the fired case fall out of the chamber afterwards or do you have to pry it out?

Slvr Surfr

02-16-12, 21:54

IG,

Could a flex hone be used to smooth out the chamber ?

Iraqgunz

02-17-12, 01:50

It's not that simple. It has to do primarily with the leade. This issue has been discussed many times. The solution is to get a real barrel chambered for 5.56.

IG,

Could a flex hone be used to smooth out the chamber ?

Tweak

02-17-12, 01:58

Iflex hone

If the chamber is cut to the proper size and the walls are scored in the process then "honing" them smooth will make the chamber oversize and most likely out of round.

strongisland

02-17-12, 08:26

A buddy of mine had a DSA that was bending the round at the neck after being chambered. I felt this was indicative of a seriously out of spec chamber. He called DSA and told them the problem and they said they would ship a new barrel out asap. The sad part is this gun was almost going to be put in service as a duty rifle. Some people I guess have to learn the hard way.

j200pruf

02-17-12, 12:26

Yeah, lesson learned. If at some point in the future would it be worth upgrading this upper with a good barrel (BCM, DD, LMT...) or should I just get an entire barreled upper?

varmint49

02-17-12, 16:11

First off you can not re-cut the chamber on this barrel because it has been chromed, unless you want to ruin the reamer. If it has nicks in it ....it is gunk,you would need a new barrel. Like Iraqguns said get rid of those o-rings and you won't get all that brass crap in the chamber.....

TacticalSledgehammer

02-17-12, 18:09

Is this DSA or Double Star Arms we're talking about? I can't comment on DSA, but I've had 2 problem free double stars. So based on that alone, I'd say it's ammo. Then maybe try a lighter buffer?

Mine would eat steel cased ammo all day long.

j200pruf

03-15-12, 17:46

I just wanted to say thanks to everyone again, after having some hassels with DSA they agreed to give me my money back. They even refunded both of my shipping charges, and for the flash hider I had to buy.
I ordered a 14.5 BCM upper today, I am hoping that it will be here before my birthday on the 27th :)

tpelle

03-15-12, 18:10

BufordTJustice

03-15-12, 21:26

HKUSP.40

03-17-12, 13:13

I ordered a 14.5 BCM upper today, I am hoping that it will be here before my birthday on the 27th :)

Now THAT'S what I call problem solving :dance3:

machinegunbob

03-21-12, 15:10

Try a Wolff extra power buffer spring along with a H2 buffer.