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 Maintenance & Troubleshooting
 Extraction Issue
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americanboy
Advanced Member


USA
363 Posts

Posted - 01/26/2017 :  08:15:18 AM  Show Profile Send americanboy a Private Message  Reply with Quote
I recently came-by an Iver Johnson. It has extraction issues. I have removed and examined the extractor. It will lock-over the case-rim and extract it on dry-runs every time, but in live-fire...it will fail to extract positively say...every 3-4 rounds. The extractor itself looks fine and I am leaning toward suspecting the extractor plunger spring. I don't have a spare spring and B4 I go on an ordering binge, I thought I would ask to see if I'm on the right track.

Anybody ever identified a weak extractor spring?

Edited by - americanboy on 01/27/2017 1:10:09 PM

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bonnie
Advanced Member



USA
171 Posts

Posted - 01/26/2017 :  09:27:52 AM  Show Profile Send bonnie a Private Message  Reply with Quote
Some other thing to look at also:

Shooting factory ammo or reloads?
Extractor spring bolt hole clean.
Chamber clean? I use a 9mm bore brush to scrub with.
Chamber rough, possible needing to be polished.
Piston nut tight?

My new USGI extractor springs measure around 7/16".
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americanboy
Advanced Member



USA
363 Posts

Posted - 01/26/2017 :  10:29:02 AM  Show Profile Send americanboy a Private Message  Reply with Quote
I put the bolt back together after I cleaned it all up. The spring-cavity was very grimy, but I failed to measure the spring. It just "feels" a little mushy to me. This being a commercial, who knows who's spring they used and very likely not USGI.

115-grain FMJ factory ammo, gas-system seems to be okay and the gun cycles well. Those are good ideas and I plan to take the bolt down and measure the spring. I don't think the chamber is sticky, as I can pull the stuck cases with little effort, but I'll revisit that as well.
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cali201
Senior Member



USA
714 Posts

Posted - 01/26/2017 :  11:06:41 AM  Show Profile Send cali201 a Private Message  Reply with Quote
those parts are cheap and easy to replace, why not put in a new spring, extractor, etc. to be sure?
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swampmolly
Senior Member



USA
764 Posts

Posted - 01/26/2017 :  12:54:40 PM  Show Profile Send swampmolly a Private Message  Reply with Quote
Aboy
Some of the springs look similar and could be installed in the wrong place, especially the extractor plunger spring.
This list may help you identify the springs.

Recoil spring: 10.25" (120 coils)
Hammer Spring (Type 1): 2.100" (22 coils)
Hammer Spring (Type 2): 2.500" (26.5 coils)
Ejector Spring: 1.05" (27 coils)
Extractor Plunger Spring: .380" (10 coils)
Operating Slide Stop Friction Spring (Type 1): .250" (7 coils)
Operating Slide Stop Friction Spring (Type 2): .380" (8 coils)
Sear Spring (Type 1): .700" (16 coils)
Sear Spring (Type 2): .655" (15 coils)
Mag Catch/Safety (Type 1): .90" overall (including 2 plungers)
Mag Catch/Safety (Type 2): 1.00" overall (including 2 plungers)
Mag Catch Plunger Spring: 1.00" overall (including single plunger, 18 coils)

Dimensions given were extracted from Craig Riesch's book, "U.S. M1 Carbines, Wartime Production".

SM
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americanboy
Advanced Member



USA
363 Posts

Posted - 01/26/2017 :  2:32:02 PM  Show Profile Send americanboy a Private Message  Reply with Quote
I'm going ahead and ordering another spring, like mentioned...not that expensive and I'll know I have the right one installed. I'll check it against swampmolly's measurements. The extractor claw is not damaged and will slid over-n-grab the case rim, tension is all I can suspect at the moment. I'll make sure and clean things up like bonnie suggested as well.
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Tuna
Moderator



3281 Posts

Posted - 01/26/2017 :  7:37:59 PM  Show Profile Send Tuna a Private Message  Reply with Quote
I would suggest that you order a full spring kit. The kits are not very expensive and with news springs and a good cleaning you should be ready to go with no problems.
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americanboy
Advanced Member



USA
363 Posts

Posted - 01/27/2017 :  1:09:28 PM  Show Profile Send americanboy a Private Message  Reply with Quote
SOLVED and the gun runs like a Swiss watch...analog or digital.

I found a spare bolt, from which I borrowed the extractor plunger and spring, which solved the extraction issue. I need to add something here, as I have never seen this particular system in/on an M1 carbine...commercial or USGI. You can't even find one to purchase. Parts sources do not offer anything like it.

The extractor plunger was a tad LONGER than USGI and the spring was a tad SHORTER. This would result in purposely reducing the extractor tension...less spring=less pressure. The only thing I can think of is that somebody was trying to reduce the wear-n-tear on the extractor and when the spring became a bit weak, extraction failed. I installed the stock USGI plunger and spring and it works very well. Maybe I'll break an extractor one day and maybe I won't, but for the time being, I'm not going to worry about it.

Edited by - americanboy on 01/27/2017 1:10:50 PM
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swampmolly
Senior Member



USA
764 Posts

Posted - 01/27/2017 :  5:35:55 PM  Show Profile Send swampmolly a Private Message  Reply with Quote
ABOY
This may answer your finding.
The type I plunger was used from the beginning of production in conjunction with the type I extractor. When the
type I extractor was redesigned the plunger was also redesigned to better engage the lip of the extractor.
The type II plunger was used throughout production. Ordnance documents indicate that the type II plunger
was to have a shorter shank than the type I plunger. Generally the shank on the type I plunger is longer
than that of the type II, however, short shank type I and long shank type II plungers are occasionally
observed.
SM
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americanboy
Advanced Member



USA
363 Posts

Posted - 01/27/2017 :  6:18:26 PM  Show Profile Send americanboy a Private Message  Reply with Quote
I vaguely remember reading something about the T1 and T2 plungers, but that information must not have stayed in my kidneys...LOL. I know that everyplace I looked there was only a listing for "a" plunger and "a" spring and not any differentiation between the two types. Obviously if you improve something, it becomes the norm and that's completely understandable. Now that I recall reading about that, I thought the difference between the two was the "step" where the plunger engaged the shelf on the extractor. This one I removed had the step and the spring that came out of it was .283 in length. A pretty far cry from your noted .380 and it had only 7 coils. The plunger itself was some .010 longer and together, they still did not reach the overall free length of the 10-coil spring and it's plunger.

What the heck. I purchased a gun from a seller that likely knew it was broken and was taking-me-in. However, I gave a fair price for it and the deal was not bad at all for me....U learn something everyday and I'll likely forget this in a month-or-so after two-or-three more problems.

Thanks for the help and insight!

Edited by - americanboy on 01/27/2017 6:19:09 PM
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swampmolly
Senior Member



USA
764 Posts

Posted - 01/27/2017 :  8:27:01 PM  Show Profile Send swampmolly a Private Message  Reply with Quote
Aboy
I have found that many secondhand carbines that can be picked up for reasonable prices will have problems. You were lucky you had good instincts and you were drawn to the problem. I think that some carbine owners do not have balls to take a bolt apart. :)
Good Job
SM
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americanboy
Advanced Member



USA
363 Posts

Posted - 01/28/2017 :  05:06:18 AM  Show Profile Send americanboy a Private Message  Reply with Quote
I can't help myself...I'm an engineer by trade. I keep stuff torn-up around here all the time. I can say one thing......the carbine bolt-tool has to be one of the best inventions known to mankind....right up there with the wheel! I'd be dangerous to society if I only had a good lathe.

I purchase used guns like I do used cars....assume there is something wrong with it, it's had the crap ran out of it...and buy it based on that assumption.
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