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Posted: 2/5/2004 10:12:59 AM EDT
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I have an AR i recently put together. i bought the complete upper, at a gun show. the problem that i am having is that every now an then a fired round gets stuck in the chamber. If you drop the mag, and cycle the bolt forward. it grabs the case, but you cant pull it out. you have to pull like heck. then the ejector just pops over the round. if you take a cleaning rod and lightly tap the case it comes right out. no noticable marks on the case ( like where there might be a bur in the chamber.) except the edge of the case where the exrtactor grabs it is mangled, sometimes ripped off. I ordered one of the defenders to put on the extractor spring but it still does it. A friend of mine said to maybe check the headspacing. Any help, or suggestions from you fella's would be greatly appriciated. Thanx |
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I had a similar problem with some 16" uppers and certain South African ammo. Long story short, the problem was that the powder had a slow burn rate, and due to the carbine-length gas system, the chamber pressure was still too high when the extractor tried to pull the case out of the chamber. The ammo worked just fine in a rifle with a 20" barrel, because the full-length gas system allowed a little more time for the pressure to drop before extraction. I bought some XM193, and the 16" uppers work without a problem. What kind of ammo are you using, and what kind of upper? |
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You have a bad chamber, or bad brass. The problem is not cases sticking to the wall too long because of the powder burn rate. No matter how long the powder burns, pressure is still down to zero, and the case free to extract, after at most 2 milliseconds. If your cases are stuck indefinitely, the chamber wall is rough, or the brass has something on its surface. |
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Why did Armalite go to the mid length gas system on the carbine? Gas pressure was still too high at the ten inch carbine length. Some powder charges were slower burning than others causing extraction problems. With the more suitable powders now that problem seems to be almost non-existent. Quoted: You have a bad chamber, or bad brass. The problem is not cases sticking to the wall too long because of the powder burn rate. No matter how long the powder burns, pressure is still down to zero, and the case free to extract, after at most 2 milliseconds. If your cases are stuck indefinitely, the chamber wall is rough, or the brass has something on its surface. |
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thanx for the help guys. i was thinking that it was a bad chamber also. i just wanted to ask some people that new more about it than i did. as for the extractor. i didnt think i had a problem there, cause it was ripping the ends of the cases off. thanx again fellas. |
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