New SIG P938 malfunctions: ideas?

1KPerDay said:

How would the length of the claw prevent full engagement? Wouldn't it be the horizontal length of the extractor shaft (parallel to the bore) that would determine that? thanks for your patience

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I originally thought this as well.

I removed the slide and took out the barrel. When I push the round into the claw, there is a little wiggle-room. Also the measurements of the space between the claw and the breach-face indicate that it is larger than a within-spec rim thickness.

So I looked at other possibilities.

1KPerDay said:

Wait, I think I get it. Friction of the too-tight claw on the outside edge of the rim? But wouldn't that hold the slide out of battery slightly?

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Yes, And I had 2 instances of failure to return to battery on my first outing as well.

The slide was 99% closed and I physically could NOT bump the slide closed with my hand. I had to remove the mag and sling-shot the slide onto the chambered round and reinsert the mag.

I only polished mine with a jewelers file after the initial reduction.

I'm not suggesting anyone do this with their gun. I'm only saying what I did and what i learned.

I removed some length and re-shaped the "angle" to make it easier to get out of the way.

Be careful of the fact that the lower "hanging" tab portion of the extractor claw is what actually pulls the round out of the chamber once the barrel tilts. It is NOT advised to remove as much from this area as from the top area which would be where the claw grabs when the chamber is in battery.

Remember there are no "Spare" parts. Only do this if you know that you may have to wait 6 months for a new extractor claw.

This is why I always like to give a new gun a good year or so on the market before I pick it up.

1kperday.

Good to hear.

Maybe it's just coincidence that my fine-tuning coincided with the break-in and it was coincidental that the gun worked well.... Maybe.



YMMV

My round count is up to 550 now. And since my modifications, i've had NO failures to extract.

I did have TWO FTF with some 147gr Winchester White Box JHP. But both were quickly cleared with the Tap-Rack-Bang... way better than the FTE jam.

Flawless with the 115's and 124's and OTHER 147s I've used. The two FTF's nose-dived into the ramp.

90gr Frangible? seems a bit light

Good price on the 98 grain. My little 938 had the FTE only with WWB. Used the American Eagle cheap stuff and had no problems. Have shot 115's up to 147's.
I do run it wet.

wtxj said:

Good price on the 98 grain. My little 938 had the FTE only with WWB. Used the American Eagle cheap stuff and had no problems. Have shot 115's up to 147's.
I do run it wet.

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I keep my guns as dry as possible.

Three thoughts on that:

#1, I don't usually find my pistols getting more-lubed as they sit in my pocket all day.
#2, I don't see as much lint caked inside the gun when it's dry as when it's wet.
#3, I don't like the thought that if i don't have Y-amount of X-product on the gun, it won't work. I like to know that even dry as the Sahara, it's going to run.

~SN13

I used to worry about the link issue, but my pocket holster seems to have cured that. I don't know but I sure do like the grease that came with my P938. Run it on the rails, run it on all of my auto rails, at this time. Keeps the wear factor to a minimum on rails.

What I'm hoping is soon as I get another 200 or so rounds down range, I'm going to run another box of WWB. I had FTE time after time when the pistol was brand new in June only with the WWB. Hoping this P938 will shoot them without any problems at that time.

Another 50 rounds through last night, only one malfunction this trip.

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A double feed - caused by failure to extract - is an extractor problem. The case should still be pulled out of the chamber, regardless of how firmly you hold the gun.

The Lone Haranguer said:

A double feed - caused by failure to extract - is an extractor problem. The case should still be pulled out of the chamber, regardless of how firmly you hold the gun.

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Precisely.

The extractor physically cannot open far enough to accept the rim of a within-spec rim on the large size.

My extractor had a 4 thousandths of an inch short-fall on it opening enough per rim diameter spec. The Rim Diameter should be .392" (9.96mm).... My claw could only open to .388"... Doesn't take a genius to know you can't fit a 9.96mm circle into a 9.85mm hole.....

OP,

Could it be a tight chamber in your P938? When you have the barrel out of the gun and hold it chamber up, will your ammo of choice drop in with a plunk? Everything I've read here points to a tight chamber, the extractor running over the rim is indicative of a chamber problem.

Just a thought and it's easy enough to check yourself. I'm pretty sure it isn't limp wristing, that seems to be the new go to excuse for gun manufacturers.

"professional artists rendering"


Lol, informative and funny!

Remllez said:

OP,

Could it be a tight chamber in your P938? When you have the barrel out of the gun and hold it chamber up, will your ammo of choice drop in with a plunk? Everything I've read here points to a tight chamber, the extractor running over the rim is indicative of a chamber problem.

Just a thought and it's easy enough to check yourself. I'm pretty sure it isn't limp wristing, that seems to be the new go to excuse for gun manufacturers.

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The extractor jumping the rim durring extraction would point to a tight chamber.... but this is not the case.
The extractor sometimes fails to get ONTO the rim in the first place.... it's an extractor issue.

Anyone ever use FrogLube on their P938?