the dreaded '3-point bind' malfunction - failure to extract

[tuj]

Hi fellow shooters!

In the last year, I have had this particular malfunction happen to me twice in two different guns of two different vintages; first in a 5906 that I bought used and now recently in a new CZ75-P07. Both times it happened using CCI aluminum case Blazer FMJ ammo.

I was able to replicate the failure with snap caps on the 5906 after trying about 100 times hand-cycling the slide. I replaced the extractor spring on that gun and have not seen the problem since. I was very surprised to see it on a new gun (the CZ) that has less than 700 rounds through it.

If you're not familiar with this particular malfunction, it's a failure to extract. The extractor somehow slips off the rim, the slide continues backwards and then comes forward to pick up the next round and shoves the next round's nose against the empty case still in the chamber. Clearing the malfunction, well, quite frankly sucks because the mag will not drop free as the top round hasn't cleared the feed lips and is bound up, so you must pry the magazine out and cycle the slide, hoping to clear the chamber, then re-seat the lead round in the magazine lips properly, then re-insert the magazine, then cycle the slide again.

What do you guys think promotes this malfunction; purely weak extractor springs or can accidentally limp-wristing cause this? Anyone know of any better ways to clear this malfunction other than how I've described?

 

[WoodchuckAssassin]

I would shine a light down the bore to see if the case was expanded/cracked. I don't like to blame the gun first. If the spent case looks fine, then I would probably blame the extractor.

 

[tuj]

Do you think aluminum case Blazer has anything to do with it? I've never had this happen with brass strangely.

 

[CPshooter]

Do you think aluminum case Blazer has anything to do with it? I've never had this happen with brass strangely.

Could be. I know I've seen a LOT of cases where the aluminum stuff won't work reliably in an otherwise reliable gun. I used to have a Glock 19 that was like this.

 

[Urban_Redneck]

If it only does it it with aluminum cases ammo... don't use aluminum cased ammo

Aluminum cases expand when fired, but, don't contract that 1/2 micron like brass cases do. A tight chamber and or a little roughness gives them enough to grab onto and defeat the extractor.

YMMV

 

[1911Tuner]

That's not a 3-Point Jam. That's a failure to extract followed by a failure to feed due to the chamber being blocked by the empty case.

 

[Jim Watson]

That is not a three point jam from stem bind, it is a failure to extract.

Any road, there are three things you can do.
Don't shoot aluminum Blazer.
Replace the extractor spring. That worked the last time, didn't it?
Czech springs aren't very springy for some reason.
Be prepared to replace the extractor.

 

[243winxb]

The aluminum does not spring back like brass when hot loaded. Try different ammo.

 

[tuj]

sorry guys, I had heard this described at the 3-point-bind malfunction on the S&W forum when I first encountered it. My mistake with terminology.

I don't use aluminum for anything but practice, but it's still a little unnerving to have your gun jam, you know? Especially for a new pistol.

 

[VA27]

Some guns just don't like aluminum, though it does give you a chance to work on your phase 2 malfunctions/practice accessing your backup gun.

 

[1911Tuner]

Back with a little time to 'splain.

For the record, a 3-Point Jam is technically a failure to go to/return to battery and occurs because the incoming bullet nose impacts low on the barrel ramp and pushes the barrel forward. When the barrel moves forward, it moves up. When it moves up too early, the upper front lug corners crash with the rear corners of the slide lugs...and it all comes to a screechin' halt.

Some 3-Point Jams chamber the round, and are accompanied by a distinct "Ka-Chunk" sound...often most noticeable on the top round when releasing the slide during a slidelock reload.

I run into a lot of 3-Point Jams that are directly caused by some goof "polishing" the feed ramp with a Dremel and a buffing head, rounding off the top corner of the ramp in the process. It doesn't take much to guide the bullet straight into the barrel ramp instead of gliding over the top as it breaks over to horizontal. The barrel ramp is actually a clearance...not a guide. At most, the bullet nose should lightly brush it as it climbs toward the top. Ideally, it should miss it altogether.

A quick way to tell if you've got a 3-Point related failure to return to battery is to push on the back of the slide. If the gun goes to battery, it's not a 3-Point and the extractor is usually the cause.

Or...When it happens...use a short length of wood to bump the muzzle straight back. No need to hit it hard. Just a light bump will move the barrel backward enough to relieve the bind...and the slide will snap to battery. If that happens...it's a 3-Point Jam.

You can cut and paste this to the S&W forum if you wish, but expect the other guy to take umbrage at being corrected.

On the failure to extract...

I've run into this a few times with Blazer aluminum-cased ammo, and the cause is always undersized rim diameters. Stir in an extractor claw that's at or below .032-inch long, and the claw can slip off the rim as it tries to pull the case out of the chamber. The fact that aluminum cases don't "spring back" as readily as brass after the pressure drops only adds to it.

 

[chris in va]

Switch to Blazer Brass. I had nothing but jams with the aluminum stuff.