Failure to extract. Rough chamber?

[DMK]

I have a Star B. Full size 9mm (9x19).

The gun will shoot, but not extract the round. After firing the spent shell remains chambered, slide closed, extractor still engaging the rim. I can manually slingshot the slide and the round extracts and ejects cleanly. Next round strips off the mag and loads just fine. It acts just like a gas gun (like a FAL, AR or AK) with the gas port plugged.

I'm thinking the chamber is a bit rough and the brass is grabbing on to it as it expands when the bullet is fired. Once the brass cools a second or two later, it contracts and allows me to extract it by manually cycling the slide. Does this seem likely?

If that is the case, what is the best way to clean up the chamber?

 

[SIGSHR]

My first suggestion is to buy a spare barrel-or 2. I have a Star Model B myself. You did not specify if this is an original or aftermarket barrel. Try another barrel,if that works fine you know the first barrel is at fault.
As far as cleaning up the chamber,I would try an abrasive or polishing compound-a very mild grade, and very gentle polishing by hand.I would put some compound on a cleaning ptach wrapped around a wooden dowel that fits the chamber very snugly, then rotate in one
direction only 3 times, then check for fit and function.

 

[DMK]

As far as I know it has the original barrel.

Do you know where I can get a replacement? Numrich doesn't have any.

I have some Flitz polish. I may try that.

 

[Scorch]

Even if the chamber is rough, it should at least try to cycle. The fact that it does not is interesting. 9X19mm is tapered, so even with a rough chamber it should cycle and extract. What does the brass look like? How hard is it to cycle by hand after firing? How hard is it to cycle by hand unfired? I am thinking it may be the recoil spring or the link rather than the chamber.

 

[Rainbow Demon]

Clean the chamber with acetone, or acetone based nail polish remover.
Some european milspec pistol ammo originally intended for SMG use has coated cases and/or thick neck sealants that can end up coating the chamber with a laquer like gunk. When the gunk is warm it grips the case, when cool it lets go.
I've seen this problem with some 7.62X25 ammo.

Some propellents can foul a chamber in the same way, though the surface of the chamber would look bright and shiny. The chamber pressure irons the fouling into the surface and the case moving against it during extraction polishes the surface.

As the crust gets thicker it can prevent the case neck from releasing the bullet as easily as it should, greatly raising chamber pressure.

Anyway, always clean the begeezus out of any firearm before you consider any alteration to springs or polishing of chambers.

 

[HiBC]

What kind of ammo are you using?

You might try a sample of plain,common brass case 9mm hardball,like the white box or Fiocchi or WW.

A 9mm chamber is not real difficult to inspect.Pull the barrel out,grt under good light,and look at it.A 10x or less loupe will look down in there.

A mechanical pencil,with the thin lead,you can drag and probe around in there,you will be able to feel any significant texture.It you can't feel the flaws with a pencil tip,probably insignificant.Silly putty does a great job of taking an impression.A gob pressed onto the chamber wall and carefully lifted off will give you something to read.Did you look at the brass?Anything strange?Gall,scrape,scratches,etc?

This is pretty much like a 1911,right?You may have what Khunhausen would call a timing issue.

How things are hand cycling is not necessarily how they are in the dynamics of firing.
Unloaded,hammer cocked,put your thumb in the guard and finger under the bushing and ease the slide back about 1/2 in.The link will pull the barrel down,you will feel the underlug of the barrel contact the frame.That is where the barrel stops.The slide continues back on its own....unless the barrel DURING THE DYNAMICS OF FIRING has not been linked down enough to fully disengage the locking lugs,with some clearance.Due to the geometry,its the forward lug that is least likely to fully disengage.

This condition is quite likely to cause damage to the locking lugs of the barrel and or the slide.Inspect the locking lugs for signs of upset or battering

Back to the test of easing the slide back to full linkdown ,barrel underlug just contacting frame,they used to sell a little kit,a srpring to force the barrel up,and a piece of narrow feeler gage,I don't remember the thickness,but lets guess .012 for nowWith that spring forcing the barrel up into the locking lugs,the feeler gage needs to slip freely between the barrel and the slide,ahead of the ejection port,assuring there is clearance between the barrel and the slide at linkdown.

 

[DMK]

Here are some pictures:

(I forgot to get a picture of the link, but it looked fine)

The barrel lugs don't look too bad to me.

I'm not seeing any peening on the lugs inside the slide either.

The spring and slide release look fine.

Some battering here. I'm not sure if this is a problem.

Here's the chamber. It actually doesn't look too bad. However, it does look like someone took a stainless steel bottle brush to it. Lots of fine scratches going around the circumference.

 

[DMK]

Even if the chamber is rough, it should at least try to cycle. The fact that it does not is interesting. 9X19mm is tapered, so even with a rough chamber it should cycle and extract. What does the brass look like? How hard is it to cycle by hand after firing? How hard is it to cycle by hand unfired? I am thinking it may be the recoil spring or the link rather than the chamber.

I'm a big dummy and forgot to collect the brass. I'll try it shooting it again this weekend and get the brass this time.

It does not seem unusually difficult to cycle after firing or just manually cycling cold.

Clean the chamber with acetone, or acetone based nail polish remover.
Some european milspec pistol ammo originally intended for SMG use has coated cases and/or thick neck sealants that can end up coating the chamber with a laquer like gunk. .

I've experienced that before with other guns, but I'm not seeing any indication of that here. I did try a good cleaning of the chamber with gunscrubber and Hoppe's #9. In my pictures, you can see it is very clean.

 

[DMK]

What kind of ammo are you using?

You might try a sample of plain,common brass case 9mm hardball,like the white box or Fiocchi or WW.

This last time it was S&B 115gr commercial hardball. I first noticed the problem a year or two ago, shooting CCI Blazer I believe. At that time, I cleaned it good, put it in the safe and forgot about it (it's always been a safe queen). The gun did fire fine when I first got it about 6 years ago or so. I'll see what I have in the 9mm department and try a few different brands if I have them.

A mechanical pencil,with the thin lead,you can drag and probe around in there,you will be able to feel any significant texture.It you can't feel the flaws with a pencil tip,probably insignificant.Silly putty does a great job of taking an impression.A gob pressed onto the chamber wall and carefully lifted off will give you something to read.Did you look at the brass?Anything strange?Gall,scrape,scratches,etc?

I'll try the silly putty trick when I get home tonight.

Under a magnifying glass and with strong light, it looks like someone took a stainless steel bottle brush and twisted it in the chamber to clean it (though it could just be toolmarks from when the barrel was made). Lots of fine scratches around the circumference. It also looks like they did the same thing to the bore, but those scratches go lengthwise.

Oddly, I compared the chamber and bore to my model 1927 Sistema and the both have the same scratches (over cleaning in service I suppose). The Systema's chamber looks much worse in fact with some pitting as well. Yet the Systema shoots and cycles just fine.

Unloaded,hammer cocked,put your thumb in the guard and finger under the bushing and ease the slide back about 1/2 in.The link will pull the barrel down,you will feel the underlug of the barrel contact the frame.That is where the barrel stops.

Easing the slide back like you say, the barrel drops and disengages the slide smoothly. I'm not seeing any battering of the top lugs.

Now the stop in the frame seems to have some battering and you can see some wear at the edges of the lower lug under the chamber. I wonder if this is from someone thumbing the slide release and dropping the slide on an empty chamber?


Thanks for your help and advice everyone!

(edited for spelling mistakes)

 

[HiBC]

Another question

When you fire it,does the hammer stay down,or does it cock?

If your hammer cocks,the slide is coming back.With strong extractor tension,the brass would stay on the breech face and re-chamber if you had a failure to eject...Short,broken,missing ejector,or rubber buffer shortening slidestroke or too strong recoil spring?

 

[DMK]

IIRC, the hammer is staying down.

But let me try and shoot it this weekend and verify that.

Failure to eject and re-chambering the spent round sounds like it could be a possibility. I need to figure out where the ejector is on this thing...

It does eject fine when I manually cycle it though.

 

[DMK]

Here's a schematic from Numrich. I'm guessing the ejector is part #03?

{Moderator edit: Link is fine, but see forum policy on posting copyrighted materials for why I took the image out}

 

[HiBC]

Yes,and so you can observe ,as the slide comes to the rear of its travel,the ejector must protrude enough from the breech face to knock the brass out.

Now,it you load one round in the mag,put the mag in the pistol,drop the slide,and fire,does the slide stay open?

If it does not,it may indicate the slode is not coming fully back.

Are you running it pretty dry,or is it lubed?

Is this a well worn gun,or new?

Arte you holding it relaxed,or with a firm grip?

 

[DMK]

Now,it you load one round in the mag,put the mag in the pistol,drop the slide,and fire,does the slide stay open?

Oh that's a good idea! I'll try that. I'll also remember to check to see if the hammer cocks after firing and save my brass this time.

Are you running it pretty dry,or is it lubed?

I tend to lube my guns pretty well. In fact I've been accused of over-oiling by some. The gun is dry now because it hasn't been shot in a while and I've been wiping it down to inspect it, but I'll oil it up before shooting it again.

Is this a well worn gun,or new?

This gun was proofed in 1943. I suspect it was a German contract gun and then captured by the Russians, due to look of the finish. It definitely has that purple look on some parts like Russian refurbs often have. All the serial numbers match though, including the barrel, so it doesn't look like the Russian armorers swapped parts on it as was also common for them to do.

So it's been around the block a few times. It did shoot well when I first got it from another collector about 8 years ago. I hadn't put more than 100 rounds through it myself.

Yes,and so you can observe ,as the slide comes to the rear of its travel,the ejector must protrude enough from the breech face to knock the brass out.

Here are some closeups of the ejector and barrel link. They look OK to me. The link moves freely.

 

[Unclenick]

On thing it occurs to me to ask is about the condition of the extractor. If the hook has lost sharpness on the inside or the if the spring has taken a set and weakened, then the hook could slip off the rim under the higher force of extraction in actual firing, then snap right back over the rim on the return to battery. You could apply some Magic Marker to the rim of the case and the leading edge of the extractor to look for signs of that happening.

That said, if the slide is truly getting all the way to counterbattery, I would expect it to try to strip the next cartridge and jam in that case. But you don't have a filed hammer nose and I can't see how sharp the bottom of the firing pis stop is, so it's perfectly possible it cocks before reaching full counterbattery, allowing what I described to happen. You can test for this with it assembled. See if you can make the slide cock the hammer without picking up an empty case you put in the magazine.

 

[DMK]

So I shot 8 rounds through it this afternoon. One round in the mag each time, using two different mags, just to make sure it's not a mag issue.

Every shot, the slide came back just enough to half cock the hammer and no more. It did not come back far enough to lock open on an empty round.

The brass had no odd marks at all. The rim is perfect all the way around.

This is what the hammer looked like after every shot.

 

[DMK]

On thing it occurs to me to ask is about the condition of the extractor.

Here are some pictures of the extractor. I stuck an empty shell in there and shook the slide around and it did hold the shell tight. I'll have to try that marker trick while shooting to see if that shows anything.

 

[mega twin]

It looks like your ammo may not have enough oomph to cycle the slide all the way back.

 

[Nathan]

Is this possibly the wrong recoil spring?

 

[Unclenick]

Agree. That hammer is only making it to half-cock. Behaves exactly like underloaded or over-aged and weak ammo in my .45 Auto 1911. That extractor claw looks fine, and the spring could still be weak, but given the half-cock, my expectation is it just isn't getting the case clear of the chamber or hitting the ejector nose, so everything slides right back in. Pick up some fresh ammo, possibly with the next heavier bullet weight and see how that does.