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Posted: 8/10/2012 7:51:28 PM EDT
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16" Midlength carbine spring and buffer m16 boltcarrier No O ring on extractor black insert in extractor spring Bolt does lock to the rear after last round when cycled by hand or fired. Rifle has fired somewhere in the neighborhood of 200-300 rounds with zero issues. Took it to the range last week and it went through at least 40 rounds with no issues. It then fired a round, extracted the round from the chamber, drove the bolt to the rear, picked up a new round, and attempted to cram both of them into the chamber. I thought it was a doublefeed at first and cleared it as such. I think I switched magazines from a US GI (green follower) to a known good Pmag with PMC bronze .223 in it. About 7 or 8 rounds later it did the exact same thing. I saved the fired cases that didn't clear the rifle and one is a PMC and the other is a Remington UMC .223. Neither of them showed signs of abnormal extractor damage or ejector marks. Did I just get two random bad rounds next to each other? |
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I am NO expert but I'd have to say that there has to be something wrong with the rounds that failed to be ejected. Ether the base is too thin or the round itself is deformed.
EX: I just started reloading 300 AAC Blackout rounds made from .223 Rem cases. I had a steep learning curve to 1) get the case necks sized correctly so that the shoulder of the case was the correct dimension 2) get the case length correct which is 1.368" and 3) to get the loaded bullet length correct which with my Hornady XP 110 grain bullets turned out to be 2.040". When I first reloaded .223 Rem rounds, it too had a steep learning curve. Reforming die setup is critical as is the bullet seating die setup. |
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Quoted:
16" Midlength carbine spring and buffer m16 boltcarrier No O ring on extractor black insert in extractor spring Bolt does lock to the rear after last round when cycled by hand or fired. Rifle has fired somewhere in the neighborhood of 200-300 rounds with zero issues. Took it to the range last week and it went through at least 40 rounds with no issues. It then fired a round, extracted the round from the chamber, drove the bolt to the rear, picked up a new round, and attempted to cram both of them into the chamber. I thought it was a doublefeed at first and cleared it as such. I think I switched magazines from a US GI (green follower) to a known good Pmag with PMC bronze .223 in it. About 7 or 8 rounds later it did the exact same thing. I saved the fired cases that didn't clear the rifle and one is a PMC and the other is a Remington UMC .223. Neither of them showed signs of abnormal extractor damage or ejector marks. Did I just get two random bad rounds next to each other? Sticky ejector is the most likely cause. This type of ejection/feeding problem is not considered as a double feed and is not mag-related. The bolt moved far enough to the rear to strip off another round, but failed to eject the spent case before doing so. Completely disassemble the bolt and remove the ejector pin and spring. Clean thoroughly, lube and reassemble. Try this and let us know if this resolves the issue. |
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Yep,bolt dropped the spent case on the way back.
As for the Black insert in the extractor spring, unless you pulled the spring out of a package with a NSN #1005014245899, don't leap to the conclusion that the black insert marker is designating that extractor spring as a extra tension unit. Seems that a lot of companies now are just throwing in black inserts into springs as a selling point, but not as the really spring marker to desinate it as the M-4 extra tension unit. Having said that, could have been a cleaning problem if you are using the wrong cleaning agent, such as Hoppes which leaves behind a protective residue that just loves to fouls up quickly in the auto loaders, the extractor spring a cheap knock off of even a standard grade extractor spring, or even just a bit of brass fouling making it way so the extractor can not fully seat home. So to sum it up, Add an #60 O ring around the extractor spring for a few hundred rounds (about a dime at any hardware store and will last you about 500 rounds) to see if the problem goes away. If by the time the O ring dies on you and its no longer used, if the problem comes back (was not just a chamber needing to be polish through live fire), then change out the extractor spring to one that you know is a extra tension extractor spring. |
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