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Posted: 7/2/2007 3:26:42 AM EDT
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I get this once every 5 rounds, with all kinds of mags and ammo. Total failure to eject. The new cartridge tries to feed and gets bent when it hits the shell still in the chamber. What could be causing this? The last thing I did, I might have overlubricated the bolt, could it have caused these FTEs? I wiped off all oil, and it got better somewhat but still happens. |
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Check your extractor claw to make sure it isn't partially broken. If the extractor checks out ok, then improve the spring tension in the extractor spring. Either get an extra strong spring, or use a Crane O-ring or a D-Fender D-ring. If the spent case is being left in the chamber, it's an extraction-related problem. |
You can get them at anyplace that sells AR parts. I'd suggest first selecting one of the vendors that supports this website. I don't sell the extra power springs, but I sell the D-Fender D-ring. Some people think it costs too much, so they buy the Crane O-ring instead. Others just buy an extra power extractor spring. Whatever you decide to do, get something to add more tension than the stock spring. |
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Dano523, Is the case being bent, hence the jam with the bolt on top of the live round, or is the live round getting bent by being feed into a spent case still in the chamber? It's the latter. The live round is getting messed up, the tip especially, by trying (and failing) to get fed into the chamber which still has the spent case. It doesn't extract. twl, Where do I get this "extra power extractor spring"? |
www.gunsprings.com/RifleShotgun/Colt_Rs.html Or you can search the vendors for a Black insert M-4 extractor spring (stronger than the standard units as well). |
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I'll ask my own question and relay my experience here instead of starting a new thread because I had the same thing happen to my 6920 yesterday. About every 10-15th round would fail to eject, very annoying, the action cycled just fine because it tried to load a new round into the chamber but ended up jamming because there was already a spent case in the chamber, the new round would have it's bullet pushed back into the case. I field stripped the gun, removed bolt from bolt carrier, removed the extractor claw. Wiped everything down, used a patch of CLP and my thumbnail to clean the extractor claw super clean, reassembled and no more failures to extract for the next 4 mags. Problem solved. So my question is can a dirty extractor cause a failure to extract or just coincidence it's working fine and I need to check into the extractor spring? Thanks |
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Well, if there's one thing I've learned, it's "never say never", because some wierd things can sometimes happen. But, I haven't seen an extractor malfunction from dirt like that. I guess it could happen. My opinion is that all carbines can benefit from a stiffer extractor spring system. Our particular unit, the D-Fender increases the extractor tension by a factor of 4x, compared against the old single spring system without any inserts. Carbines need some pretty strong tension on that extractor, because the way a carbine cycles is pretty demanding on that part. |
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Bravo Company has everything you need in one kit for $5. The D-fender would also work but is expensive. BTW a Blue extractor spring insert is for a rifle and the black insert is for a carbine. I say always use the black if it's a rifle or a carbine. |
The stronger Colt black insert extractor spring was an improvement that allows the M-4 to work with a wider assortment of ammo's (like the extended feed ramps), and came into play much later from when the standard carbine rifles where first offered. On a standard rifle or standard carbine using standard ammo in a true Nato chamber, a correctly tensioned Blue insert spring is the correct factory spring. |
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This page seems to describe the problem well: http://www.armalite.com/library/techNotes/tnote56.htm Anyway, I installed a new extractor and a blue extractor spring. I also cleaned everything extensively. Should know shortly what difference this makes. Question, does the extractor and the bolt face need to be lubricated? |
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