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bjarni

M4 Extraction Problems

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I'm having a bear of a time with my DPMS M4 carbine extracting. I've tried different brands of ammo, but I've still got around a 50% failure to extract. I even sent the weapon back to DPMS (who were very cool about paying all the shipping expenses) who test fired it with "no malfunction". Now I've installed a Buffer Technologies D-fender extractor spring stiffener, but I haven't had a chance to fire it yet.

Any thoughts?

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Try replacing the tiny spring under the extractor itself or get a totally new one to replace the one on the bolt. It shouldn't cost that much if you have to pay for it. IT could be bad magazines as well causing the weapon to not feed right. If all else fails send her back.

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Is the extractor jumping the rim and leaving the brass in the chamber or is it just jamming on extraction? If it's the latter, try replacing your ejector spring.

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It's jumping the rim, or it WAS!! Celebrate with me, brothers. Went to the range today to see whether the Buffer Technologies D-fender I installed did any good, and . . . guess what? It worked like a champ! It's like a different gun. I'm in love again. :wub:

So pass it on, anyone having AR15 extraction problems, for a mere $12.95 and about a minute's labor, you can fix it.

ok>

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Buffer Technologies D-fender as stated above - works great, I have a couple of extras in my kit SN/

Hey, Blue. Any other bits of wisdom you want to share with a fellow M4 lover? For example, what Manufacturer is yours, mine's a DPMS? How about favorite ammo?

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I'm having a bear of a time with my DPMS M4 carbine extracting.  I've tried different brands of ammo, but I've still got around a 50% failure to extract.  I even sent the weapon back to DPMS (who were very cool about paying all the shipping expenses) who test fired it with "no malfunction".  Now I've installed a Buffer Technologies D-fender extractor spring stiffener, but I haven't had a chance to fire it yet.

Any thoughts?

13440[/snapback]

I have had the same failure-to-extract issues as you (with the same brand receiver) while using a 16" barrel. My problems seemed to be directly related to the ammo that I used. Some ammo worked fine, Some did not...

The 'hot' ammo seemed to cause me more problems vs the 'normal' stuff.

Some ammo creates much more pressure than others as we all know...

I believe that the problem is caused because of the difference in gas pressure between the 16" and 20" barrels. Stoner designed the gun to work around a 20" barrel with it's longer gas tube. When you shorten the barrel (and gas tube) length, the volume of gas which is cycling the action of your gun changes considerably and can oftentimes cause problems.The 'hot' ammo I have used was causing the gun to try and cycle WAY too fast (and then fail to extract), While the 'normal' ammo caused very few problems at all. I have seen others at the range solve this problem with the use of an adjustable-gas-block. The block allows us to fine-tune the cyclic rate of our guns to suit ANY ammo we may feed it.

I can see how the D-fender piece may help alleviate the problem, but I believe the cause to be gas-related. IMO the best solution to this problem would be to use an adjustable gas block to try and more closely simulate the gas pressures of a 20" barrel. I tend to look at the D-fender like putting a band-aid on an oil leak. Yeah, The 'leak' has stopped, but what caused the 'leak' in the first place?

Stoner designed an awesome gun, But changing the barrel length from 20" to 16" (and shortening the gas tube in the process) changed many things that affect the overall way that the gun functions (ie; Cyclic rate, Gas pressures)

Sometimes when you change/tweak one thing, You have to tweak others as well to get things back in sync. The Adjustable Gas Block lets us tweak what we changed (the volume of gas). Once we can get our gas pressures back within the 'normal' limits for this gun, The 'Failure-to-extract' issues will be over...

Can you tell I spend WAY too much time studying this crap? B{

Good Luck with your gun, Hope I have helped...

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Hey AR-Tech, welcome to the forums. I agree with everything you said.

Hope you stick around and help us with your expertise.

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Hey AR-Tech, welcome to the forums. I agree with everything you said.

Hope you stick around and help us with your expertise.

94478[/snapback]

This web site is awesome! ok> Thanks for the welcome!

I got a bad feeling that my wife is going to be mad at me... {cry}

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I got a bad feeling that my wife is going to be mad at me...  {cry}

My wife says these forums are my way to relieve stress. I tell her I'm not stressed - I cause others to be stressed. :rofl:

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Try replacing the tiny spring under the extractor itself or get a totally new one to replace the one on the bolt. It shouldn't cost that much if you have to pay for it. IT could be bad magazines as well causing the weapon to not feed right. If all else fails send her back.

13463[/snapback]

New Member... I have had extraction problems with my rifle as well. Symptoms include: Failure to extract with or without loaded magazine, Failure to extract with or without magazine installed, and although this has not occurred often, part of the rim of fired round is sometimes ripped off by the extractor. Most often however, after firing a round that doesn't eject, manual ejection via charge handle can be performed with absolutely no resistance what so ever. I have suspected possibly a rough chamber that is preventing round from ejecting while case is still expanded. If this is the case, how can it be resolved?

Any ideas?

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New Member... I have had extraction problems with my rifle as well. Symptoms include: Failure to extract with or without loaded magazine, Failure to extract with or without magazine installed, and although this has not occurred often, part of the rim of fired round is sometimes ripped off by the extractor. Most often however, after firing a round that doesn't eject, manual ejection via charge handle can be performed with absolutely no resistance what so ever. I have suspected possibly a rough chamber that is preventing round from ejecting while case is still expanded. If this is the case, how can it be resolved?

Any ideas?

110302[/snapback]

http://www.hk94.com/hk/index.php?showtopic=11588

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