will not strip rounds, whats up?

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livesound41

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Hi all I need some advice.

I shot my new 2007 m305 a few days back. It originally had an out of spec bolt, so I had it replaced with new USGI bolt and new internals at one of the docs clinics.
The gas system is correctly aligned and snug , as well as the gas plug.
So I went out to sight it in and have a bit of fun, fired 4 mags no problem of Norinco green box. Then I reloaded and started to run another cycle of 4. The first mag good, the 2nd had two failures to strip a round, but did cycle. So I had to recycle the bolt to load those 2. Mag 3 was fine on the 1st but would not strip rounds on the next 4. Mag 4 2nd round fired but would not extract and was jammed good.
Trigger hammer was stuck in a position of about 75% of its travel,(which I could push back with a wood dowl) but the bolt did not seem as if it was fully rotating to release. I pulled on the op rod to no avail; I did observe that the bolt roller seemed to be correctly positioned in the track.
I was able to retract the hammer, pull the trigger group, remove barreled action from the stock. Then I moved the bolt back and forth for a while and assisted its travel from below to eventually extract the empty round. So what is going on? Is this a case of too tight of a chamber for the ammo?
I'm stumped
 
If I am reading correctly, there appears to be two issues. The first was replacement of the bolt to USGI. I had the same issue when I replaced mine. The issue with that one is that if you compare measurements, you will find, at least on mine, that my new USGI bolt was significantly larger in (vertical) dimension than the Norky bolt and was very tight to push back over the trigger hammer. The energy to move the bolt backward is obtained from the gas of the fired cartridge. In my case, there simply was too much friction absorbing the energy (spring, round in mag and trigger group) and the bolt was not travelling far enough.

My fix was to purchase heavier springs and lap the bolt/trigger group hammer to reduce some of the friction. That resolved my issue. Unless you know what you are doing, I would not suggest you attempt this as you can really screw things up if not careful. I have the tools and an industrial air compressor and was very careful as to where the lapping compound went.

My rifle functions flawlessly now.

As to the non-extraction, it might be related to the same issue, only compounded by the Op-rod sliding out of it's track. Did that occur? It also might be an ammo issue. When you stripped the rifle, did you happen to notice if there was an excessive wiggle or tell -tale markings on the op-rod in the location of the guide?
 
Put an empty mag in so you can lock the oprod back.
Tip so muzzle is pointed up and push piston into cylinder. Remove finger rapidly and observe piston drop.
Does it drop slower with some vacuum?
Or does it drop like a stone.

If I remember right, we lapped that bolt in for 1.630 headspace back in 2009 at the clinic at my house in langley (?)
Sounds like you have a perfectly good excuse to drive on over to my place for a couple days of deer hunting/fishin/m14 tunin :D
 
"...headspace?..." Has nothing to do with feeding issues. I'd start by changing the ammo. Then I'd be looking at the mags. They buggered, I mean, altered 20 round mags? I'm wondering if whatever is making 'em 5's has come loose somehow.
 
Stock oprod spring and guide rod? Or aftermarket NM type?
I'll keep firing questions at ya. Look for the simple stuff first, rule it out, then move on.

Mags could be the culprit if they are a rivetted type and rivet is interfering with full lock up of the mag catch.
And.... "Some" short barrelled rifles seem to have issues with the norc ammo but run fine with others.
I solved this on one rifle after many many frustrating weeks, by slightly increasing the internal volume of the gas plug itself. At least one guy I know tried everything and finally enlargened his barrel's gas port (not recommended by the way)

Could be so many things from dead nutz simple to not so simple
 
45ACPKING said:
Put an empty mag in so you can lock the oprod back.
Tip so muzzle is pointed up and push piston into cylinder. Remove finger rapidly and observe piston drop.
Does it drop slower with some vacuum?
Or does it drop like a stone.
Click to expand...

My 22" barrel Norc's gas piston drops like a stone. Seems like there's no vacuum. Shouldbi be concerned?

(Sorry to go off thread)
 
If your rifle has cycling issues absolutely.
Piston needs to have some vacuum or it can allow too much gas blow by and not enough into the piston body to reliably cycle. Generally you get many thousands of rounds between piston changes but, these parts do wear out
 
Just home from work; so I am reading everyones suggestions and questions. 1) mags are the same ones I use with my other m305(always buy 2) and they work fine in that gun. 2)original op rod spring replaced with a USGI Wolf over a Fulton armory fluted spring guide, so lots of jam.3) op rod never came out of the track at all and tracks well. 4) Hey Thomas, the gas system seems good. I did as you suggested and the piston comes back slow with reasonable vacume. 5) Bolt was lapped in place by Laz I think and spec confirmed by those around the table. Good lug contact, and I can not test headspace myself but Thomas I believe you are right. Not super tight chamber; rather good for 308 and 7.62x51 both. I did notice the op rod seemed to be lacking extra grease where it tracks through the guide, so I added some and more to the spring and guide as well. So op rod moves easier now, but does that explain failure to feed?
 
I forgot to mention we are talking about a full length 22 barrel on a gun that has just experienced its first 30 and a few rounds before jamming up. Hopefully we will figure this out yet.
 
If you still have your original spring and guide... Try them
I've seen a few guys post in the past that this solved their specific cycling issue.

Another thought... Is the oprod arm rubbing on the stock near the forward part of the arm? Just throwing simple things to check before looking for larger issues

So hard to diagnose from the keyboard
Oh, hey , my back ordered bolt rollers are shipping, there's a couple clips n rollers in there for ya ;)
 
I checked the op rod ,and no rubbing to report; however I have noticed that as the bolt goes forward in counter recoil it has a tendency to hang up a bit on the rear left lug in the side of the receiver. On closer inspection I can see what seems to be dremel tracks in that area that are not smooth but rather gouged.Is this a possible problem?
 
LOL I answered yer p.m. And thought you were talking right bolt lug.

Got any pics of the binding/dremlled area?
Any burring on your bolt?
 
Cases stuck in the chamber binding up the bolt , might.....
sunray said:
"...headspace?..." Has nothing to do with feeding issues. I'd start by changing the ammo. Then I'd be looking at the mags. They buggered, I mean, altered 20 round mags? I'm wondering if whatever is making 'em 5's has come loose somehow.
Click to expand...


Have you done the tilt test? If it passes I would not worry to much about the left lug. The machining marks are pretty rough. I hope there are no dremel marks, I'm sure laz would have noticed.

1.630 is tight for surplus 7.62. My 1.630 chamber will fit S&B and Federal .308 but not PPU 7.62
 
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Ummmm

Was that baby full of grease?

* bolt lugs x 2
* bolt raceways
* op rod guide and op rod interface
* op rod track
* hammer face and nose (look for the wear marks, you will see them)

Often people forget to grease all these contact points and it makes for sloppy running of the M14. Grease will smooooooth out the entire cycling process and eliminate some/many FTE's and FTF's.

Cheers,
Barney
 
I forgot to suggest something previously, which was triggered by Thomas's comments about the piston. Have you tried with different ammo? I found my M14 is really fussy with ammo. Once I tuned it, with handloads it likes the 4895 or 748 (with mag primer) at about 2,700 and 2750 fps.

Before doing any messing around, try using a box of Winny or Remington ammo - 150's and see if problem persists. I know with my 308, i shoot some of that MFS and my M14 loads and she tends to bark and kick a little harder with my loads...and they are not loaded hot.
 
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