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Ejector problem

Printed From: The Carbine Collector's Club
Category: The Club
Forum Name: General Discussion
Forum Description: Carbine Related
URL: http://www.uscarbinecal30.com/forum/forum_posts.asp?TID=3834
Printed Date: Mar 28 2024 at 2:56pm
Software Version: Web Wiz Forums 12.01 - http://www.webwizforums.com


Topic: Ejector problem
Posted By: Charles
Subject: Ejector problem
Date Posted: Jan 08 2019 at 9:23am
My S'G' functions beautifully except when clambering a spent round. Some time ago, the range guard at N R A instructed me to, as a safety precaution, chamber a spent round. When I attempted to eject it, it locked up. It took a wooden dowel down the barrel and a tug to the slide to eject it. Thought I'd not do that again.
Yesterday during one of my occasional foundling my (carbine) I did it again.
Question, does anybody know W T H H happened?


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Charles
Co B 1st Batl.115 Inf. Reg.
29th. Divi.
4.2 Heavy Mortar Co Retired
Life member NRA




Replies:
Posted By: W5USMC
Date Posted: Jan 08 2019 at 10:05am
I believe that once the round is fired that the case expands and even lengthens a bit, by chambering the spent casings you are jamming something that is no longer sized correctly into the chamber causing it to get stuck.

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Wayne
USMC Retired
NRA Life Member


Posted By: Uncle Mike
Date Posted: Jan 08 2019 at 10:18am
Hi, W5USMC is absolutely correct. I did the same thing trying to function test a firearm. I now use these..
https://www.brownells.com/gunsmith-tools-supplies/general-gunsmith-tools/cartridge-dummies/centerfire-rifle-dummy-rounds-prod40859.aspx" rel="nofollow - https://www.brownells.com/gunsmith-tools-supplies/general-gunsmith-tools/cartridge-dummies/centerfire-rifle-dummy-rounds-prod40859.aspx
 
regards, Mike


Posted By: blackfish
Date Posted: Jan 08 2019 at 10:21am
It;s difficult to see how a spent case could be difficult to EJECT (thrown off the bolt face). What you probably mean is that you find it difficult to EXTRACT (remove from the chamber). These are two separate events in any semiauto's firing cycle.

A further note, the case does expand to a larger diameter when fired but since the volume of metal forming the case is fixed (brass is neither created nor destroyed), the case must SHORTEN to compensate. For the same reason, when the case is sized, its diameter decreases and its length "grows back".

If you size the spent case, then it will extract (and eject) just fine. But I fail to see any utility in chambering a spent round. The fun is over.


Posted By: Charles
Date Posted: Jan 08 2019 at 11:35am
I should have mentioned, I did measure the length of the case and it was still within specs as far as length is concerned and it did chamber easily. So, back to the drawing board.
I do appreciate all the help and looking for more theories.
The key word is extract, not eject.


-------------
Charles
Co B 1st Batl.115 Inf. Reg.
29th. Divi.
4.2 Heavy Mortar Co Retired
Life member NRA



Posted By: jackp1028
Date Posted: Jan 08 2019 at 12:13pm
How about this for a theory? The carbine case and chamber are both slightly tapered (.0175"/inch). Yes, it can expand a little when fired but it will not expand to a size larger than the chamber unless the case is allowed to move rearward in the chamber during firing. Also, when it cools after firing, it will shrink back a little and should not be tight. This assumes there is no axial movement of the case in the chamber. However, if the headspace is excessive, then the case might back out a little during firing allowing it to expand more than normal and thus be tight when pushed all the way back in.

Check your headspace.

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JackP


Posted By: floydthecat
Date Posted: Jan 08 2019 at 12:50pm
Chambers, due to wear or manufacturing, my not be “perfectly” demensial....not precisely round. A fired case may or may not wind up perfectly round as it forms to the chamber when fired. Unless you can perfectly chamber the fired brass in the exact position in which it was fired and from the same weapon.....it very likley will not fit perfectly. Of course, it may not fit perfectly at all anyway for some of the reasons listed.

I have attempted to slopply check head-space on fired brass in another weapon and quicky discovered the cases stick.


Posted By: sling00
Date Posted: Jan 08 2019 at 1:03pm
As stated, fired cases expand.  Hence the resizing step when reloading.  Ever tried to resize a casing without proper lube?  I pretty well destroyed a case beating it out of the die.  Dummy rounds and Snap Caps are best for functional checks.  Also work pretty good for getting an enbloc to "PING". 


Posted By: New2brass
Date Posted: Jan 08 2019 at 1:12pm
The carbine headspaces on the front of the case. Hence the length of the sized case is important.
Is it possible that absent of the projectile to retain the shape that the front of the case is slipping past the chamber into the lands and grooves?

Is it a little difficult to pull the slide back because the extractor picking up the case but releases due to the case being stuck? 
Or does the slide pull back normally as if it is not latching on to the case?


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http://www.uscarbinecal30.com/forum/club-assistance-saginaw-receivers_topic4716.html" rel="nofollow - Club Survey Saginaw Receivers


Posted By: Charles
Date Posted: Jan 08 2019 at 1:41pm
Dan, not discounting others reply's,but yours seems the most likely. I hadn't thought about the absence of the ball allowing the casing to jamb in the chamber shoulder.
I think we are on to something. I just ordered a 10 piece  set of snap caps.
Thanks Dan.


-------------
Charles
Co B 1st Batl.115 Inf. Reg.
29th. Divi.
4.2 Heavy Mortar Co Retired
Life member NRA



Posted By: sling00
Date Posted: Jan 08 2019 at 3:04pm
OK, forget the casing expansion. I figured one way was to give it a try so...Used 4 fired cases of 4 mfgs, FC, AGUILA, W-W, and LC 52. All loaded with full bolt closure and hammer dropped without sticking. By any chance did you attempt to load the case from a mag?  I don't think you could if you tried but I'll ask.  That would deform the mouth of the case. 


Posted By: jackp1028
Date Posted: Jan 08 2019 at 3:19pm
Dan, the dimension across the lands is .300" +.002. The specification for the O.D. of the mouth of the case is .328" minimum. That means that the case must collapse at least .026" overall or .013" per side for it to jam into the lands and grooves. That's more than the wall thickness of the case and should result in visible marks on the mouth of the case.

Charles, if the case is jamming on the lands you should be able to see evidence of this in the form of "rifling" marks on the end of the case or perhaps the case being deformed into a "squarish" shape on the end. Are you seeing this?

Also, do spent cases "jam" if pushed in by hand with the bolt rearward? I don't believe you can push hard enough with your fingers to deform the case. I may be wrong. If they still jam, it might be something else.

The only reason I am beating this dead horse is because if it is caused by excessive headspace, it could be dangerous. Please check your headspace.

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JackP


Posted By: Charles
Date Posted: Jan 08 2019 at 3:28pm
No, I hand fed it. Also one more point, It was a steel case but didn't pull the trigger. Apparently, steel is not as strong as brass. From this experience, I highly recommend snap caps.
Best of all, I am grateful for all of the support from the forum members.
Charles


-------------
Charles
Co B 1st Batl.115 Inf. Reg.
29th. Divi.
4.2 Heavy Mortar Co Retired
Life member NRA



Posted By: sling00
Date Posted: Jan 08 2019 at 3:41pm
Originally posted by Charles Charles wrote:

From this experience, I highly recommend snap caps.

Me too.  Here's some vintage dummy rounds...
https://www.libertytreecollectors.com/productcart/pc/viewPrd.asp?idproduct=8907" rel="nofollow - https://www.libertytreecollectors.com/productcart/pc/viewPrd.asp?idproduct=8907


Posted By: New2brass
Date Posted: Jan 08 2019 at 5:11pm
@ Jack, I have never slugged a carbine chamber. Nor have I held a carbine chamber reamer.
The one time I did the first few thousandths on the lands were cut or worn. this would reduce your calculations ever so slightly.
If there is some buildup in the chamber this might lead to a "ramp" effect to get the case started into the lands.
Dunno?


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http://www.uscarbinecal30.com/forum/club-assistance-saginaw-receivers_topic4716.html" rel="nofollow - Club Survey Saginaw Receivers


Posted By: sling00
Date Posted: Jan 08 2019 at 5:26pm
Found this thread on AR15s, "You should periodically scrub the chamber thoroughly with a chamber brush if you are using steel cased ammo a lot. Steel cased ammo does not fully expand in the chamber, allowing carbon to blow back into the chamber, which can cause stuck cases after the carbon builds up. A overly tight chamber can expedite this process."


Posted By: W5USMC
Date Posted: Jan 08 2019 at 5:29pm
Originally posted by Charles Charles wrote:

Some time ago, the range guard at N R A instructed me to, as a safety precaution, chamber a spent round.


Just to keep it simple I say don't chamber a fired casing. I do however question this "range guard's" thought process, I know if I was acting as a range safety officer I would much rather see an empty chamber as a safety precaution on the firing line than a chamber with a spent round it it.


-------------
Wayne
USMC Retired
NRA Life Member


Posted By: jackp1028
Date Posted: Jan 08 2019 at 5:49pm
@ Dan, me neither. Also, if the throat of the chamber is eroded that could also create a ramp effect as well. In either case, it's a problem that will affect headspace. The original specification calls for a .005" radius maximum on the transition from chamber to rifling. There is no forcing cone like ramp in a carbine. That's a pretty sharp ledge and I think it would take a considerable amount of force to jam. Since the carbine head spaces on that surface I believe it should be checked. It could save Charles from a face full of hot gasses.

Steel cases are another factor that could contribute to this phenomenon. I know this is controversial but I have had bad experiences with steel cases in my AR's. Haven't tried them in my carbines. Rumor is they often have some kind of coating (polymer or lacquer or something) on them to prevent corrosion and aid in extraction. That coating supposedly can build up in the chambers of firearms not intended for their use and and cause them to stick. Tough on extractors, allegedly. Like I said, I've never tried them myself...in my carbines, that is.

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JackP


Posted By: painter777
Date Posted: Jan 08 2019 at 8:47pm
Off Topic 

Detailed Comparison of Brass cased vs Poly or Lacquer coated Steel cased Ammo.
AR15....... Lengthy, but interesting:

https://www.luckygunner.com/labs/brass-vs-steel-cased-ammo/" rel="nofollow - https://www.luckygunner.com/labs/brass-vs-steel-cased-ammo/

FWIW,

CH-P777


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Living Free because of those that serve.....



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