Misfire Troubleshooting

[murray]

Dang!!! We get 21 bucks to check head space and it takes all of 5 minutes. Not sure what that 'Smith is actually charging for. And if there is excessive head space, beyond a "Field" gauge, then the only remedy is a new bolt. Any corrective modifications he is referring to should be explained and prices given for this work.

Yes, the rough filed nature of the surface that engages the Locking Shoulder makes me concerned there might be too much head space. If you had too little head space, you could have some trouble getting rounds into the chamber, on occasion, and misfires would not have been your primary problem.

Did I mention we sell new Made in USA (by Wolff) factory original strength 34 lb Hammer Springs, as well as 31 lb Hammer Springs, and Wolff's original 27.5 lb Hammer Spring?

[Boris Badinov]

Could the carrier be the culprit here?

OP: what is the serial number on the bolt carrier?

I ask because often the serial number will reveal national origin.

Perhaps the carrier is not Chinese, but from another national variant?

[Andronicus]

Could the carrier be the culprit here?

OP: what is the serial number on the bolt carrier?

I ask because often the serial number will reveal national origin.

Perhaps the carrier is not Chinese, but from another national variant?

Here is the image of my bolt carrier.

[Andronicus]

This is becoming a recurring pattern.  I was out shooting on Saturday, and after 50 or 80 rounds, I was having the spent casings not fully extract, jamming on funny angles as the bolt closed. 

To me, and I could be wrong, this seems like an incomplete cycle.  I pulled the gas tube off to check the gas piston, but it was still moving freely.

UPDATE

I did some shooting this weekend.  The incomplete extraction issue seems to be rectified.  Previously when this was reported, I had lost the temporary pin that holds the furrel to the gas tube.  I suspect I was loosing some gas.  Since I have purchased and installed a proper pin.  This problem did not re-occur.

I am still having the misfire issues.  I'll post a few pictures of the misfired shells. 

[Andronicus]

Here is a comparison.  The one on the right misfired, the one on the left fired normally.  The misfired shells always fire fine when fired a again.

If I understand everyone correctly, seems the leading theories are
1) Too much headspace
2) Mismatched bolt/receiver (too much headspace again)
3) Not enough hammer spring tension?

I did take off a bit of metal from the sear to get positive engagement.  Could I have buggered up the hammer tension?

As the cost of using a GO/NO GO gauge is quite high, I am first going to try a method posted on this board by someone using feeler gauges at the locking shoulder (firing pin removed of course).

[Rocketvapor]

You can't compare primer strikes between misfired and fired primers. 
In addition to a good hard hit from the firing pin a fired primer is hit with about 30,000psi from the inside. 

[Boris Badinov]

It could be as simple as the ammo you're using.

Try another brand of ammo.

Or even more of the same, but with a different headstamp.

[Andronicus]

It could be as simple as the ammo you're using.

Try another brand of ammo.

Or even more of the same, but with a different headstamp.

I have used surplus ammo from two different tin cans, but from the same Cabala's store, so quite possibly the same lot.  I could splurge and buy some actual Wolf or BarnauL ammo...

[murray]

I'd start cheap. Our 31 lb Hammer Spring is likely to stop most all misfires, or you could even go with a factory original strength 34 lb Hammer Spring. Spend about 10 bucks and instantly resolve whether it's just a weak Hammer Spring or not.

[Andronicus]

I'd start cheap. Our 31 lb Hammer Spring is likely to stop most all misfires, or you could even go with a factory original strength 34 lb Hammer Spring. Spend about 10 bucks and instantly resolve whether it's just a weak Hammer Spring or not.

I think there are some venders up here in Canada that sell your hammer springs.  I'll Check it out.

[murray]

We sent HiCal some earlier this year but a little pricey. You could order the 31 lb RPP Set from us, add shipping and it's the same $ as theirs, before shipping. They list it as a "Wolff" product but you can't buy it from Wolff.

[Andronicus]

We sent HiCal some earlier this year but a little pricey. You could order the 31 lb RPP Set from us, add shipping and it's the same $ as theirs, before shipping. They list it as a "Wolff" product but you can't buy it from Wolff.

I see that.  I'm just debating whether to buy a sear at the same time...

[murray]

The Sear is machined and stoned for a smooth "positive" engagement with the Hammer, but you might need to remove a little material from the ears of the Hammer that contact the Rebound Disconnector, for proper fit and function. Otherwise, you'll like it. Shoot us an email and we'll send a copy of our Installation Instructions that HiCal probably doesn't provide.

[Andronicus]

Last week I installed the 34lbs hammer spring from Murray's, plus a new sear and sear spring.  It all seems to work very nice now.  Very smooth trigger pull!

Initially, when I installed the hammer spring, it appeared that the new spring was making contact with the disconnector bar, causing a restriction the disconnector bar's movement.  This resulted in the trigger bar's incorrect engagement with the sear.  It appears rotating the spring 180° has solved that problem. 

I'm eager to head out and try shooting with these new parts.

[Andronicus]

I finally got out shooting again on Monday (30 Dec).  With the new setup (new hammer spring, sear and sear spring), I still had 2 failure to fire malfunctions with about 200 rounds fired.  That is a big improvement. 

The biggest improvement in the trigger pull.  WOW, Murrey's new sear made the trigger pull amazingly smooth.