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Posted: 1/18/2015 11:31:18 AM EDT
This is a friend of mine's Bushmaster 16 inch with a carbine length gas tube. It's a standard configuration and nothing has been modified by him. He told me that he got to fire one round and then this happened. He didn't take the gun to the range after that. I figured maybe it was an extractor issue so I had him bring it over and I replaced the extractor spring and put in a BCM extractor upgrade with the beefier spring and O ring, etc.
He took it to the range and said the same thing happened again. It looks like the extractor is ripping the rim of the cartridge off, but the case is still stuck in the chamber. He sent a couple of pictures to me. He mentioned that maybe he should replace the whole BCG, but if it's a different issue, then he just wasted a hundred bucks. He's been using American Eagle 5.56 ammo. What do you think it could be?   |
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Posted: 1/18/2015 11:37:54 AM EDT
[#1]
Could be a manufacturer error, port too small. Not getting enough gas to cycle properly.
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Posted: 1/18/2015 11:39:03 AM EDT
[#2]
If the spent casing can be removed, clean the chamber.
Did he clean the chamber before he first fired it? Also, hard to tell, but it looks like there are rough chamber markings on the spent casing in the photos. |
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Posted: 1/18/2015 11:50:13 AM EDT
[#3]
Quote HistoryQuoted: If the spent casing can be removed, clean the chamber. Did he clean the chamber before he first fired it? Also, hard to tell, but it looks like there are rough chamber markings on the spent casing in the photos. |
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Posted: 1/18/2015 12:05:46 PM EDT
[#4]
Quote HistoryQuoted:
You think the chamber can be that dirty on a brand new firearm? Dirty, I can understand but dirty enough to have the case jammed in there so hard that the extractor rips the rim off? Quote HistoryQuoted:
Quoted:
If the spent casing can be removed, clean the chamber. Did he clean the chamber before he first fired it? Also, hard to tell, but it looks like there are rough chamber markings on the spent casing in the photos. KBAD was trying to point out that the fired case looks like it has a ring imprinted on it from a crappy chamber, not that the chamber was dirty. need a better picture of the fired case, side shot, no shadows please. |
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Posted: 1/18/2015 12:14:12 PM EDT
[#5]
Looks like it is trying to extract while cartridge is still stuck to chamber.(Over-gassing)JMHO
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Posted: 1/18/2015 12:16:38 PM EDT
[#6]
Many rifles are shipped with a rust preventative coating that is very tacky, and will cause problems with extraction. It needs to be removed. Some CLP on a GI chamber brush followed by patches would do the trick.
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Posted: 1/18/2015 12:42:50 PM EDT
[#7]
If the chamber brush doesn't do the trick, then it would be a gassing issue?
Posted Via AR15.Com Mobile |
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Posted: 1/18/2015 12:45:22 PM EDT
[#8]
Correct. Polishing the chamber is the first easy step, generally.
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Posted: 1/18/2015 12:48:05 PM EDT
[#9]
As previous guys suggested, there may be crud in the chamber, or it may have a burr. With rifle pointed in safe direction (preferably at a range), manually cycle rounds by loading a full mag and pulling charging handle all the way back and letting it fly. Do this a few times. Remove firing pin if you want to reduce chance of ND. If rounds cycle smoothly, problem is likely in gas system.
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Posted: 1/18/2015 12:50:08 PM EDT
[#10]
Quote HistoryQuoted:
Could be a manufacturer error, port too small. Not getting enough gas to cycle properly. Please dont give sarcastic answers to tech forum posts. carbine may be over gassed or it may not have a true 5.56mm chamber and throat. Or it may be a combo of both like a couple of bushmasters I own. |
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Posted: 1/18/2015 12:51:12 PM EDT
[#11]
Quote HistoryQuoted:
As previous guys suggested, there may be crud in the chamber, or it may have a burr. With rifle pointed in safe direction (preferably at a range), manually cycle rounds by loading a full mag and pulling charging handle all the way back and letting it fly. Do this a few times. Remove firing pin if you want to reduce chance of ND. If rounds cycle smoothly, problem is likely in gas system. NO! |
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Posted: 1/18/2015 12:55:05 PM EDT
[#12]
Sounds like a timing issue, if polishing the chamber doesnt work.
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Posted: 1/18/2015 12:56:33 PM EDT
[#13]
Quote HistoryQuoted: NO! Quote HistoryQuoted: Quoted: As previous guys suggested, there may be crud in the chamber, or it may have a burr. With rifle pointed in safe direction (preferably at a range), manually cycle rounds by loading a full mag and pulling charging handle all the way back and letting it fly. Do this a few times. Remove firing pin if you want to reduce chance of ND. If rounds cycle smoothly, problem is likely in gas system. NO! |
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Posted: 1/18/2015 12:59:10 PM EDT
[#14]
Quote HistoryQuoted:
As previous guys suggested, there may be crud in the chamber, or it may have a burr. With rifle pointed in safe direction (preferably at a range), manually cycle rounds by loading a full mag and pulling charging handle all the way back and letting it fly. Do this a few times. Remove firing pin if you want to reduce chance of ND. If rounds cycle smoothly, problem is likely in gas system. After I replaced the extractor spring, I did cycle it several times and the rounds ejected just fine. I did fire or six in a row at a time a few times. That's what makes me wonder about the chamber. Posted Via AR15.Com Mobile |
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Posted: 1/18/2015 1:00:10 PM EDT
[#15]
Quote HistoryQuoted:
do not remove firing pin as StevenH said. You could get BCG stuck in upper if cam is allowed to rotate without the firing pin installed. Quote HistoryQuoted:
Quoted:
Quoted:
As previous guys suggested, there may be crud in the chamber, or it may have a burr. With rifle pointed in safe direction (preferably at a range), manually cycle rounds by loading a full mag and pulling charging handle all the way back and letting it fly. Do this a few times. Remove firing pin if you want to reduce chance of ND. If rounds cycle smoothly, problem is likely in gas system. NO! Roger. I wasn't thinking of doing that, though. Posted Via AR15.Com Mobile |
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Posted: 1/18/2015 1:03:59 PM EDT
[#16]
What fixed my bushmasters (that used to fail to extract with M193 in hot weather) was opening the throat with a Michiguns chamber reamer.
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Posted: 1/18/2015 1:13:07 PM EDT
[#17]
Quote HistoryQuoted:
Please dont give sarcastic answers to tech forum posts. carbine may be over gassed or it may not have a true 5.56mm chamber and throat. Or it may be a combo of both like a couple of bushmasters I own. Quote HistoryQuoted:
Quoted:
Could be a manufacturer error, port too small. Not getting enough gas to cycle properly. Please dont give sarcastic answers to tech forum posts. carbine may be over gassed or it may not have a true 5.56mm chamber and throat. Or it may be a combo of both like a couple of bushmasters I own. You mean they shipped a .223 and labeled it a 5.56? Posted Via AR15.Com Mobile |
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Posted: 1/18/2015 2:01:43 PM EDT
[#18]
Quote HistoryQuoted:
You mean they shipped a .223 and labeled it a 5.56? Posted Via AR15.Com Mobile Quote HistoryQuoted:
Quoted:
Quoted:
Could be a manufacturer error, port too small. Not getting enough gas to cycle properly. Please dont give sarcastic answers to tech forum posts. carbine may be over gassed or it may not have a true 5.56mm chamber and throat. Or it may be a combo of both like a couple of bushmasters I own. You mean they shipped a .223 and labeled it a 5.56? Posted Via AR15.Com Mobile Very common. If you "trust" the markings on the bbl then that trust is based on many assumptions. First that the seller even knows the difference and cares. Second that the company that cut the chamber knows the difference and cares. Third that if the company that cut the chamber knows and cares and used a sharp 5.56mm reamer that still cuts a true 5.56mm chamber. Not a worn or dull one that no longer cuuts a proper 5.56mm chamber. I "trust" Colt, BCM & LMT to ship with a true 5.56mm chamber. Ive had enough "bad" Bushmaster Bbls that I bought my own Michiguns reamer. You can always call Bushmaster and ask them to explain the differences between a 5.56mm vs .223 chamber and throat and what steps they take to ensure a true 5.56mm chamber and throat during chambering and to verify after chambering. The answer might impress you or terrify you depending on who you speak to and their willingess to answer. |
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Posted: 1/18/2015 2:23:50 PM EDT
[#19]
Quote HistoryQuoted:
You think the chamber can be that dirty on a brand new firearm? Dirty, I can understand but dirty enough to have the case jammed in there so hard that the extractor rips the rim off? Quote HistoryQuoted:
Quoted:
If the spent casing can be removed, clean the chamber. Did he clean the chamber before he first fired it? Also, hard to tell, but it looks like there are rough chamber markings on the spent casing in the photos. Yes clean the chamber. I was talking with one of our best 1911 smiths last week about 1911 malfunctions. We both agreed that it's due to the operator not knowing what to do and how he firearm functions. Not everything is "out of spec". Take the gun apart, clean then try it. |
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Posted: 1/18/2015 4:33:57 PM EDT
[#20]
Ditto, sides of the brass looks like the chamber has never been cleaned correctly from the start.
So chamber brush with CLP is in order to scrub the chamber to get it clean by hand, and the chamber brush needs to be used every cleaning with CLP to clean the chamber each cleaning. |
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Posted: 1/18/2015 5:02:25 PM EDT
[#21]
Quote HistoryQuoted:
do not remove firing pin as StevenH said. You could get BCG stuck in upper if cam is allowed to rotate without the firing pin installed. Quote HistoryQuoted:
Quoted:
Quoted:
As previous guys suggested, there may be crud in the chamber, or it may have a burr. With rifle pointed in safe direction (preferably at a range), manually cycle rounds by loading a full mag and pulling charging handle all the way back and letting it fly. Do this a few times. Remove firing pin if you want to reduce chance of ND. If rounds cycle smoothly, problem is likely in gas system. NO! Good point, never thought about that. |
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Posted: 1/18/2015 5:06:34 PM EDT
[#22]
Quote HistoryQuoted:
Good point, never thought about that. Quote HistoryQuoted:
Quoted:
Quoted:
Quoted:
As previous guys suggested, there may be crud in the chamber, or it may have a burr. With rifle pointed in safe direction (preferably at a range), manually cycle rounds by loading a full mag and pulling charging handle all the way back and letting it fly. Do this a few times. Remove firing pin if you want to reduce chance of ND. If rounds cycle smoothly, problem is likely in gas system. NO! Good point, never thought about that. It will stick in there like a bastard. A short firing pin is a good tool to have on hand. |
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Posted: 1/18/2015 6:56:13 PM EDT
[#23]
Quote HistoryQuoted: Please dont give sarcastic answers to tech forum posts. carbine may be over gassed or it may not have a true 5.56mm chamber and throat. Or it may be a combo of both like a couple of bushmasters I own. Quote HistoryQuoted: Quoted: Could be a manufacturer error, port too small. Not getting enough gas to cycle properly. Please dont give sarcastic answers to tech forum posts. carbine may be over gassed or it may not have a true 5.56mm chamber and throat. Or it may be a combo of both like a couple of bushmasters I own. |
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Posted: 1/18/2015 8:13:29 PM EDT
[#24]
Quote HistoryQuoted: Looks like it is trying to extract while cartridge is still stuck to chamber.(Over-gassing)JMHO My guess also |
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Posted: 1/18/2015 9:25:36 PM EDT
[#25]
As has been suggested , always start with the simple stuff . Clean the chamber like a demon and inspect the used brass .
Could be as simple as grit in the chamber "grabbing" the brass . Might have a rough spot or two in the chamber that will work itself smooth with a bit of shooting if the chamber is kept clean. Might be a chamber that is cut poorly that will never fix itself. The way I am reading this is a fairly new factory gun? Right? If so clean , lube and continue to shoot. If it still is doing that after 2 or 300 rounds contact whoever built it |
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Posted: 1/18/2015 11:07:59 PM EDT
[#26]
Photos not show markings on the brass very well.
But the brass casing looks like a reload to me. It's too marked up and dirty to be a virgin empty. The crimp at the primer is the giveaway. Yes, you can see the remain of an old crimp ring on the brass, but it is not holding the current primer in. I'd be worried about the rounds being improperly manufactured reloaded rounds. The primer isn't showing signs of overpressure, but the markings on the casing and the rim being ripped off are signs of too much pressure. |
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Posted: 1/19/2015 12:35:30 AM EDT
[#27]
Any chance to get some side pics, and pics of the neck & throat area of the empty cases that were stuck? If you are ripping the lip off the empty case, and the empty case is left behind in the chamber, this is not due to weak extraction. When the extractor is ripping the lip off the case, it has plenty of extraction strength, if it was weak then it would slip off. When the casing is left behind in the chamber with the lip ripped off the case, generally these are now removed by using a cleaning rod down the muzzle to push the empty case out. So when you use the rod to push it out does it come out easy or does it have to be forced out. If it has to be forced out, then we need to figure out what is holding the empty case in the chamber. If the empty case comes out with minimal effort, then it is possibly due to a timing issue.
For process of elimination on maintenance & lubrication, start with a thorough cleaning of the barrel using a bore brush and 1-pc cleaning rod, then a thorough cleaning of the chamber using a chamber brush and rod. Once the fouling in the chamber and barrel are scrubbed loose, wipe and rinse with denatured alcohol to remove any traces of oil/grease/solvent. Then once everything is clean, lubricate the 7-lugs of the bolt and rails of the bolt carrier with Slip2000 "EWL" Extreme Weapons Lube, so it is a wet and glissening like a glazed donut. Then try shooting the rifle again, and try some other ammunition. If the rifle is still failing to extract, then it is possible that there is a timing issue, or the chamber is too tight, and that is where I would suggest contacting Bushmaster since it is a new factory built rifle. CY6 Greg Sullivan "Sully" SLR15 Rifles TheDefensiveEdge.com (763) 712-0123 |
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