(ADVICE NEEDED) 10.5 Norc Upper Issue

greentips said:
Looks like you have an undergas situation or there are "drags" in the system.

Your MFS Russian made ammo could be on the weak side as well which may not have enough pressure to actuate the system.

Try some other ammo - such as American made winchester .223 or AE .223. Also, try some other magazines such as Pmag or GI mags to make sure it is not that the magazine which is dragging the bolt carrier. Put your buddy's bolt carrier group into your rifle to see if it is the BGC that is out of spec.

Your situation has nothing to do with buffer weight or extractor spring.

If trying all the above and it still won't work- it should go back to the factory for warranty repair.
Click to expand...

This is the best answer yet.

You install a heavier (H2) buffer to tame a violent action and limit bolt bounce. The heavier the buffer, the worse the rifle will feed weak powered ammo. This is not your problem.

In all liklihood, the MFS 55gn is the problem. Even MFS62gn is hit and miss in an AR15.

Try different ammo and different mags. To me, your issue looks to be entirely related to short-cycling.
 
Also, I am not sure where you are located.

If your ammo is weak already, or your system is on borderline, cold weather will make the situation worse. Take a weak .223 ammo for a test drive out in -10 C may not give you the same reliability as a milspec 5.56 ammo.
 
I had the same issues with a brand new AR that was simply not lubed properly.

As GT mentioned if it is cold where you are shooting it can gum up whatever lube you are using and slow the whole system down enough to do the same thing.
 
I don't have anything to add other than listen to greentips on this issue.

Try a different ammo first, check for bolt carrier being out of spec and try different mags, preferably ones that belong to a friend and have been used (so you know there are no mag related issues). Also as mlehtovaara said, make sure your AR is properly lubed with something that won't gum everything up at lower temperatures.
 
I'm happy this thread was made. it might save me some trouble, when I come back from the range saturday ;)
 
With the above information it should be narrowed down to:
-extractor spring
-ejector
-get a lighter buffer
anything else?
 
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johhny12gauge said:
So if I can chime in here (exact same problem). I used Mil spec ammo, gun lubed properly, everything appeared to look fine and the mags run excellent. I was told it is not a gas issue by the distributer. With the above information it should be narrowed down to:
-extractor spring
-ejector
-get a lighter buffer
anything else?
Click to expand...

Did the distributor have the upper in their possession? - I'd think that without taking the FSB off and miking the port, it would be very hard indeed to diagnose a potential gas problem. If they did have the upper - which their confidence would indicate, why did they send it back non-functional, if they didn't have the upper how the f*ck would they know one way or the other? Did they say what the issue was, if not why not? Just curious.
 
I have no issues with mine Norinco 10.5" upper with its original and ArmaLite,Dlask and STI lowers. I also try different type of mags, LAR-pistol mags, BushMaster etc. Ammo- PMC 55g BTFMJ, American Eagle55g and Norinco 55g FMJ...fired hundreds of rounds...no problems...and its accurate as hell!.
I hope this help.
Picture1048.jpg
 
Diagnosing Gun issues over the internet is like doing brain surgery blindfolded...

Since its ejecting cases - its not an issue with ejector or extractor.

Your gun is short stroking.
There are several possible causes.

1) ammo -- shoot a known decent round first.

2) carrier key leak

3) Gas Block Leak (either between barrel and FSB or Block and gas tube)

4) unreasonable friction in the system; this could be mag on bolt carrier, bolt and carrier fit. gas tube to carrier key, buffer dragging in buffer tube etc.

5) improperly sized gas port (or incorrectly located port).



If you have not cleaned the gun try to take a look at the carrier key - if there a lot of carbon 'leaking' from it -- usually up front near the cut for the cam pin.

Look at the gas block -- is there carbon streaking around the block/ barrel -- or the gas tube (a little is normal).

Take the bolt out of the carrier - look for abnormal wear marking inside the carrier where the bolt rides -- and damage to the gas rings.

With the bolt out of the carrier - slide it in the upper -- see if it mates with the gas tube easily.

Take out your buffer, look at the buffer tube for signs of chatter.

If you do not see any of the above -- try to plug and pay parts from a buddies gun - if you can isolate a part by swapping its a lot easier.

Frankly now that I saw the ammo, I'm not surprised, it may cycle a gun in Fl, but not in Canada in the winter...




Do not go cutting springs - that hamster gunsmithing at its best.
 
Failure to Eject (casing does not exit weapon, and is sometimes rechambered) and Failure to Eject with Bolt Override seems to be what your describing rather than Failure to Extract (casing left in chamber).

Failure to eject can be (typically) one of two things; ejector issues (either weak spring, burr on the ejector, or brass in the pocket making it mushy), or the gun is cycling too fast for the casing to clear the ejection port.
Given your desciption I would say your having ejector issues.

Quick and Dirty way is to put some drops of CLP (or another lube) on the ejector
CLPonEJECTOR.jpg

and place a piece of fired brass under the extractor
EjectorExercise.jpg

and rock it down on the ejector (so its flush with the bolt face.
EjectorExercise2.jpg


Then after doing this a few times invert the bolt and bang it on a flat surface (you'll be surprised the crap than can accumulate in there).

If this does not solve the issue, your probably looking at needing to pull the ejector and clean the pocket throughly, replace the ejector spring, and check for burr on the ejector pocket and on the ejector itself.
 
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