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Posted: 6/4/2016 8:15:34 PM EDT
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I'm having an issue with FTEs, as the title says. The issue is by no mean consistent, and some limited testing I have done appears to rule out magazines and ammo. That leaves either a bad extractor, a really overgassed rifle, or a combination of the two.
The issue appears most occur most likely with rapid fire, however it is no guarantee. I did one mag dump with no issues, and after letting the rifle cool a few minutes the next magazine experienced multiple stoppages. Does anyone have any thoughts on what I can do to remedy this? Is there any other potential causes that I am not considering? For references, the upper in question is a 16" barrel with midlength gas. I am using a semi-auto carrier and a standard carbine weight buffer. I have reason to believe my rifle is overgassed based on casings ejecting rather violently at 4-5 o'clock. By failure to extract I am describing a situation in which the fired casing is remaining in the chamber, with the bolt completing a full reward travel and picking up another round, with the stoppage occurring when the new round encounters the casing in the chamber. |
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On my middy's and carbines I run a full auto carrier, Bravo Company Extractor spring and bumper ( No O Ring). ,and a "H" Buffer. I pretty much feed them Federal M193 or M855 ( Both loaded pretty hot).
This system seams to work well for me. Another thought is also clean your chamber with a Chamber Brush with a good bore solvant on it. My Daugter's M4 started doing the same thing . I come to find out she was only using Gunscrubber and no chamber brush. 5.56 ammo sometimes has a sealant around the bullet that can build up in the chamber. |
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Quoted:
On my middy's and carbines I run a full auto carrier, Bravo Company Extractor spring and bumper ( No O Ring). ,and a "H" Buffer. I pretty much feed them Federal M193 or M855 ( Both loaded pretty hot). This system seams to work well for me. Another thought is also clean your chamber with a Chamber Brush with a good bore solvant on it. My Daugter's M4 started doing the same thing . I come to find out she was only using Gunscrubber and no chamber brush. 5.56 ammo sometimes has a sealant around the bullet that can build up in the chamber. ^^Try this. I run the BCM extractor springs and also the Sprinco extractor upgrade kit. I believe I got my Sprinco kit from Larue because it was cheaper shipping than Sprinco. ETA: Larue link. It doesn't say Sprinco but I am 99.99% sure that's where it comes from since it's the same picture. |
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Quoted:
On my middy's and carbines I run a full auto carrier, Bravo Company Extractor spring and bumper ( No O Ring). ,and a "H" Buffer. I pretty much feed them Federal M193 or M855 ( Both loaded pretty hot). This system seams to work well for me. Another thought is also clean your chamber with a Chamber Brush with a good bore solvant on it. My Daugter's M4 started doing the same thing . I come to find out she was only using Gunscrubber and no chamber brush. 5.56 ammo sometimes has a sealant around the bullet that can build up in the chamber. This. A new extractor spring (current Colt copper color, BCM, Specialized Armament, Wolff) after giving the chamber a good scrub with a chamber brush and inspect the lip of the extractor to ensure it isn't rounded off (or just poorly machined). Next would be an H buffer if needed. |
| So for now it sounds like replacing the extractor springs and giving the chamber a good scrub is in order. I don't believe the extractor claw itself is the issue (as the stoppages are not consistent), but it will probably be the next target if the springs don't work. |
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Binding/failure to extract on rapid fire only, leads to either wrong solvent or incorrect cleaning of the chamber, the wrong lubed used to lube the bearing surfaces of the upper receiver, the chamber side walls less than mirror smooth, or a problem with either the gas block or Key to carrier having a slight leak that increases as the heat builds up instead.
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