anyone seen a M1 caarbine bolt get shatttered
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URL: http://www.uscarbinecal30.com/forum/forum_posts.asp?TID=3154
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Topic: anyone seen a M1 caarbine bolt get shatttered
Posted By: JR's GunWorx
Subject: anyone seen a M1 caarbine bolt get shatttered
Date Posted: Nov 04 2017 at 8:44am
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Hopefully the picture uploads. Have a customer who brought in his M1 carbine with a shattered bolt. Blamed steel cased ammo. Trying to verify if such could be the case as I have my doubts. Anyone else see a bolt get shattered by steel case ammo? Thanks John ------------- Thx John |
Replies:
Posted By: Charles
Date Posted: Nov 04 2017 at 9:15am
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I'v been shooting steel casing ammo for years without any problems. Could they have been improperly hand loaded? A dirty left lug has been known to cause a bolt to brake as well. Inspect the area of the action were the left lug would be for burs. Also heavy scraping marks on the left lug. Hope this has been helpful. Your photos failed to show up. ------------- Charles Co B 1st Batl.115 Inf. Reg. 29th. Divi. 4.2 Heavy Mortar Co Retired Life member NRA |
Posted By: JR's GunWorx
Date Posted: Nov 04 2017 at 10:01am
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that's what I suspect also. Not the current owner, yet perhaps some past owner. Yes, found some burrs and rough stops on lug area of the receiver on both sides. Smooth those out. When I tested the fit of a replacement bolt, it operates smoothly and seems to lock up well. Now, if would be great if I can get the extractor to get in place while holding the ejector in. Extractor spring is strong! As it should be. ------------- Thx John |
Posted By: New2brass
Date Posted: Nov 04 2017 at 10:46am
Are you using a bolt tool? Here is an article on doing it without a bolt tool, however it is highly recommended that a bolt tool be used for ones sanity. http://www.uscarbinecal30.com/forum/bolt-disassembly-assembly-without-bolt-tool_topic1280.html" rel="nofollow - http://www.uscarbinecal30.com/forum/bolt-disassembly-assembly-without-bolt-tool_topic1280.html As linked at bottom of that article is the bolt page http://www.uscarbinecal30.com/bolts.html" rel="nofollow - http://www.uscarbinecal30.com/bolts.html at bottom is instructions using bolt tool.
------------- http://www.uscarbinecal30.com/forum/club-assistance-saginaw-receivers_topic4716.html" rel="nofollow - Club Survey Saginaw Receivers |
JR's GunWorx wrote:Posted By: JR's GunWorx
Date Posted: Nov 04 2017 at 11:04am
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I noticed that sanity issue without the bolt tool. And as expected, after I ordered a bolt tool, it came together as it should have in the first place. :) ------------- Thx John |
Posted By: sleeplessnashadow
Date Posted: Nov 07 2017 at 6:07pm
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I'm a little late on this one. It's not possible to determine what may have caused the bolt to shatter without a photo or a detailed description of what broke, where and other details. Steel case .30 carbine ammo isn't going to break a GI bolt. Not even in the long run. You'd have more success trying to beat someone to death with a rubber chicken. It can break the GI extractor over time. "Shatter" implies the bolt broke like glass. The most common break is the right bolt lug breaks off with the crack starting in the opening for the extractor and extending to the point the rear of the right lug connects to the body. One thing that can cause the right lug to snap off is anything that impedes the movement of the left lug as it moves back and forth in the receiver. This puts added pressure on the right bolt lug from the slide as it moves back and forth. Sometimes something as simple as a burr in the path of the left bolt lug is enough to do it over time. Easily remedied by gently filing or polishing the burr til it's gone. Here's an example of the right lug having snapped off due to burrs in the path of the left bolt lug.  Half way down the web page on bolts there's an explanation with an additional pic to illustrate why it broke. http://www.uscarbinecal30.com/bolts.html" rel="nofollow - http://www.uscarbinecal30.com/bolts.html I still have the bolt. Next time I do pics I'll take a few more showing the break from different angles. Same bolt...  Jim |
Posted By: manteo97
Date Posted: Nov 07 2017 at 8:00pm
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Have seen a broken bolt like the one in sleeplessnashaodow's post. A customer brought his carbine into me (Dad's bring back Inland), and had broken the original bolt AND a commercial replacement bolt. Barrel had been replaced by a "qualified gunsmith". Receiver was deformed in left bolt lug area too, beyond repair I checked headspace with the broken bolt and it swallowed the NOGO. Mic'd out the depth of chamber and it was .050 deeper than the NOGO dimension. So, it would seem if the chamber has been reamed way to deep, too much play in the bolt during firing, the spent cartridge recoils back a bit before it slaps against the bolt face (rather than being held firmly in place) and bingo! There goes the right lug. So, if you can, check the headspace with gauges. |
Posted By: bonnie
Date Posted: Nov 07 2017 at 9:45pm
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Some times things just break? Many years ago during a CMP club match a new from rebuild CMP "white bag" club carbine had the right lug break on a flat bolt during a match. Couldn't determine a reason why. It was fitted with a new round bolt and works just fine to this day. |
Posted By: carbinecanuck
Date Posted: Dec 04 2017 at 7:38pm
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Just had this 'N14' marked bolt come apart on me this past weekend. I haven't been playing with carbines for a very long time. I get the impression it is not a very common occurrence. Just some bad luck I guess. The bolt was hot blued post war at some point. Other than that, did not notice any signs of anything unusual about it. The carbine was quite new to me, and I only had a chance to put about a dozen Winchester FMJ through it prior to it failing.     ------------- Courage is fear holding on a minute longer. - GEORGE S. PATTON |
Posted By: floydthecat
Date Posted: Dec 05 2017 at 7:43am
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I'm sure there are no records anyone is keeping on broken bolts, but I had an N14 crack myself and it seems that the N14 shows up often in discussions concerning cracked bolts. I just steer-clear of any NPM flat bolt. Reading a lot about N14 cracks and having one crack myself, was enough to convince me. |
Posted By: sling00
Date Posted: Dec 05 2017 at 9:10am
Sounds like good advise. It would be interesting to have one inspected to determine the failure mechanism.
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Posted By: W5USMC
Date Posted: Dec 05 2017 at 11:23am
Yep, that is pretty convincing to me too. I think from now on when I shoot my Postal Meter, I will use a spare bolt instead of the N 14.
------------- Wayne USMC Retired NRA Life Member |
Posted By: manteo97
Date Posted: Dec 05 2017 at 5:51pm
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carbinecanuck is sending this broken bolt to me, along with the carbine. I'll be able to do a bit of a metallurgical examination on it. I'll post the results. |
Posted By: New2brass
Date Posted: Dec 09 2017 at 6:31pm
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Hmm, I have a N 14 bolt with a crack. This is the third mentioned here. coincidence or are we on to something
------------- http://www.uscarbinecal30.com/forum/club-assistance-saginaw-receivers_topic4716.html" rel="nofollow - Club Survey Saginaw Receivers |
Posted By: GotSnlB28
Date Posted: Dec 09 2017 at 10:45pm
fyi your bolt has its original finish - when manufactured they were dulite finished. Over the years I have seen more than a few posts where other carbine owners experienced cracked N14 bolts. |
Posted By: carbinecanuck
Date Posted: Dec 09 2017 at 11:19pm
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I am familiar with the Du-Lite finish. But this one was hot blued. Along with the rest of the barreled action. I am almost certain of that. ------------- Courage is fear holding on a minute longer. - GEORGE S. PATTON |
Posted By: carbinecanuck
Date Posted: Dec 10 2017 at 10:05pm
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Just took possession of an S.G. mixed parts carbine this weekend. The seller had notified me prior to the sale that the bolt it was coming with, was unusable. Take one guess as to what marking was on the left lug .....      It seems as this is turning out to be something a bit more than pure coincidence. ------------- Courage is fear holding on a minute longer. - GEORGE S. PATTON |
Posted By: floydthecat
Date Posted: Dec 11 2017 at 8:51am
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I hadn't paid much attention to the problem, until I cracked one. It seems as if every where I went I was reading comments concerning N14 failures. The issue has been mentioned on just about every forum I visit. As far as I'm concerned...N14 bolts are only for looking at and not for shooting. |
Posted By: New2brass
Date Posted: Dec 11 2017 at 1:20pm
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I have not done the math to say that there is an issue with these bolts. As a matter of fact there is not enough reports of broken bolts to suggest one is more prone to break than another. A little birdie tells me that you can have one of these bolts. https://www.ebay.com/itm/US-GI-WWII-1942-43-M1-CARBINE-BOLT-ASSEMBLY-NATIONAL-POSTAL-METER/192370233824?hash=item2cca28d1e0:g:idEAAOSwYlRZM0rD" rel="nofollow - https://www.ebay.com/itm/US-GI-WWII-1942-43-M1-CARBINE-BOLT-ASSEMBLY-NATIONAL-POSTAL-METER/192370233824?hash=item2cca28d1e0:g:idEAAOSwYlRZM0rD what is interesting is this one is for the ubber rare 1942 NPM  ------------- http://www.uscarbinecal30.com/forum/club-assistance-saginaw-receivers_topic4716.html" rel="nofollow - Club Survey Saginaw Receivers |
Posted By: manteo97
Date Posted: Dec 11 2017 at 10:37pm
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A quick review of past CCNL's indicates N14 marked flat bolts were used from Dec '43 to Feb '44 or later based on barrel dates, and other data. This would be roughly 4.1 mil S/N range and higher. NPM made these bolts in-house, apparently the number (8, 9, 11, and 14) indicate drawing and/or design changes. Union Switch & Signal also made UN marked bolts under contract, and these are found towards the later part of production. So, that kind of indicates maybe 150,000 or more M1 carbines came out of the NPM factory with N14 bolts. |