M305s -- FTF, FTEs -- help!

R

romurra

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Back at the range after a series of upgrades to my 2011 M305s, and now getting both FTFs and FTEs.

upgrades include:

  • wolff springs in bolt (extractor and ejector springs)
  • wolff spring on op rod.
  • M14 doc op rod spring guide
  • springfield stock (replacing norinco plastic)
  • clinic with the artist previously known as M14Doctor, with the usual mods (gas unitizing, op rod guide tightened, barrel indexed, etc.)

Rifles pass the 'safety check' and the tonyben 'tilt tests' as at <http://m14forum.com/reference/89158-tilt-test-what-why-we-do-3.html> with flying colours. Chamber is clean. Rounds feed from mag fine, and rifle always goes into battery with bolt properly seated (as far as I can see, bolt lugs in place all the way down) when the action is let go.

At the range, I get a 'click' and no bang, primer shows a light strike. Firing pin is free to move, was inspected for burrs etc. when bolt springs upgraded.

When trying to cycle/eject, the case remains in the chamber as if the extractor has not grabbed it at all, yet the bolt has gone fully into battery when the action was let go (no riding of action forward, just pulled all the way back and let fly). Snap caps at home cycle as per normal, extractor grabs them just fine (308 snap caps of course).

Ammo was Norinco brass case, all I had with me for this range trip. This was also the first range outing for my M14s with the norinco ammo, previously had been using federal american eagle with no issues. While the harder primers could be part of the FTF issue (and I will take some AE to try next time), the FTE is perplexing since snap caps work and real rounds don't work.

Any tips for trouble shooting this? suggested sequence of fixes/ analysis?

thanks all
 
I would remove the bolt and examine the proper installation of the extractor and ejector, springs, etc. Something might not be right there, and the failure to extract is a clue.
 
I would do as Grizzlypeg said first ! I had a problem with the bolt one time and it was the spring for the ejector from Wolf did not work in my Nork bolt !
Try taking the bolt out and put a round in the bolt face and make shure that the extractor and ejector are moving as they should .
I am in Van as well if you need to use a bolt tool let me know good luck .
 
"This was also the first range outing for my M14s with the norinco ammo, previously had been using federal american eagle with no issues."

Sounds like you should go back to using reliable Federal ammunition: a second range trip will confirm if you suspect the Norinco ammo. to be the problem. Two rifles, same problem? I'd say the ammo. is your problem.
 
The norinco 7.62x51 is hot and is harder to extract in all the rifles I have shot it with. I suspect it's a combination of that terrible ammo and the changes you made to the extraction system.

mafia_hit.gif
 
i changed the bolt springs (ejector/extactor) to get ejection normalized to allow scope use. i was getting stovepipes under the scope with the norinco springs. none of the norinco ammo fired, but I only tried it in the M305s, not having another 308 with me.

bear in mind, none of the FTEs were post- firing, all the FTEs were unfired rounds, so the 'heat' of the ammo should not matter (yet).
 
If you can't extract an unfired cartridge from a closed bolt, something is wrong with the extractor install. Take it apart and examine it.
 
Exactly, yet the snap caps cycle like champs at home, and the real ammo fails at the range. Repeated cycling has chewed up the snap caps now so further cycling isn't likely yo tell me much till I get new ones

Grizzlypeg said:
If you can't extract an unfired cartridge from a closed bolt, something is wrong with the extractor install. Take it apart and examine it.
Click to expand...
 
Did the extractor spring get installed properly? Sometimes, if wedged, it will jam the ejector claw and will result in limited movement of the claw. It could explain the symptoms you described. That little spring is always tricky and care has to be made to ensure that it is properly set into the recess on the extractor during installation (and not forced too much).
 
sobo4303 said:
Did the extractor spring get installed properly? Sometimes, if wedged, it will jam the ejector claw and will result in limited movement of the claw. It could explain the symptoms you described. That little spring is always tricky and care has to be made to ensure that it is properly set into the recess on the extractor during installation (and not forced too much).
Click to expand...

looks ok, moves ok, and grabs a rim out of the rifle -- any other troubleshooting tips?
 
further troubleshooting, update. re-assembled the bolts to original spec. tested 'push back' from ejector and springiness of the extractor.

ejector very stiff with wolff spring, so much so that it is hard to get the cartridge base to seat on the bolt face. perhaps this is holding the shell off such that I am getting light strikes when it goes into battery? I trimmed 1 coil off the spring, it seems similar to Norinco resistance now.

extractor seems similar to Norinco spec without changing the spring. good movement, nothing stuck or wedged.

tried cycling with snap caps, a-ok (as it was before). but they have soft aluminum lips that I think the bolt was grabbing without it seating properly, or otherwise grabbing the soft aluminum in a way it could not grab the harder brass that made it look like the cycling was correct when it was not.

also cycled with spent casings, and watched when drawing back the bolt to see the casing lip seated under the extractor. this also checks out ok.

off to the range soon to see if that fixes the problem.

has anyone 'upgraded' to wolff springs in their bolt, and if so, did they work out of the package or did they require trimming/ tuning? that seems to be my problem. maybe.
 
has anyone 'upgraded' to wolff springs in their bolt, and if so, did they work out of the package or did they require trimming/ tuning? that seems to be my problem. maybe.
Click to expand...

For what it's worth I changed to USGI because of my ARMS 18 mount. The ejection pattern went from forward to rearward and ended the case between the op rod issue.

No trimming.
 
UPDATE:

all is well.

trimmed 1 coil off the wolff ejector springs (which did measure to GI spec lengthwise, but were perhaps a bit too strong). other wolff springs used as-is. because of the shape of the bolt, i could not confirm the depth of the hole for the spring.

cycled about 25 rounds with no issues.

seems that the wolff ejector springs were too much as delivered.

as i mentioned in a previous post, the springs were so strong that after hooking a case lip under the extractor i could not bring the case base against the bolt face, no matter how much i leaned into it. snap caps appeared to work when cycling the action, perhaps because of their softer aluminum material.
 
Sounds as if the ejector was pushing the cartridge far enough that the firing pin couldn't indent the primer satisfactorily.
In all the work you've done, have you checked headspace?
 
i will stay with the setup as is for a while at least.

standard norc bolt
wolff springs, with the ejector clipped one coil

I changed to try to eliminate a stovepiping problem with the Promag ARMS 18 style mount, and it looks like it is gone now.

seems to fire all ammo ok now

I don't think tighter headspace would have helped, i think the rifle would have just not gone into battery due to the tough ejector.
 
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