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Posted: 8/28/2009 5:53:33 PM EDT
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I have an LMT SS 14.5" barrel and it has what I would call a sticky chamber. It is chambered for and fires 5.56 fine, but sometimes an unfired cartridge will get stuck in the chamber and I have to use the charging handle and a rap on the bench to dislodge it. I have tried polishing the chamber with JB and it helped some, but not completely.
What else can I do to fix this problem? Thank you. |
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Quoted:
I have an LMT SS 14.5" barrel and it has what I would call a sticky chamber. It is chambered for and fires 5.56 fine, but sometimes an unfired cartridge will get stuck in the chamber and I have to use the charging handle and a rap on the bench to dislodge it. I have tried polishing the chamber with JB and it helped some, but not completely. What else can I do to fix this problem? Thank you. Are you shooting reloads?? |
| I had this problem with my 1st Colt SP1.. It did this about 4-5 times in the 1st 500 rounds and has never done it since. I have put well over 5,000 rounds through since. It never did it with the Fedral ammo only the Winchester SS-109 and remington garbage I quit shooting later as it was filthy. |
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Quoted:
I have an LMT SS 14.5" barrel and it has what I would call a sticky chamber. It is chambered for and fires 5.56 fine, but sometimes an unfired cartridge will get stuck in the chamber and I have to use the charging handle and a rap on the bench to dislodge it. I have tried polishing the chamber with JB and it helped some, but not completely. What else can I do to fix this problem? Thank you. How often do you clean the chamber with the chamber brush? Any pitting or gouges in the chamber? BSW |
| Let me answer a few of your questions. I've shot approximately 300 rounds through the carbine and it is very well maintained. I clean the chamber (and I do use the chamber brush) and both the barrel and chamber are in great shape. I thought the chamber might be slightly undersized. Is there something that might be slightly more aggressive (than the JB) that I could use for the chamber? Otherwise, I'll keep shooting, cleaning and polishing it. |
| same thing happened to my Stag, cept i think it was due to using wolf ammo and not letting it cool down. i think that the lacquer was maybe baking off in the chamber if i shot too much too fast and a spent casing would get stuck in the chamber and i would have to pound it out with a cleaning rod. needless to say, i dont use wolf anymore. |
| Its not good to change chamber size. With the rifle clean and the carrier out ––-push a round in the chamber by hand ––-when tilted up that should fall out what a little shake. If it doesnt come out easy the ammo is not correct or the chamber too tight. If some work ok and others stick ––its the ammo. If the chamber is too tight then I would send it back to the manuf. If its sticking only at times it probably ammo related or an extractor problem. (Sometimes) an unfired round get stuck ?? That sounds like an ammo problem and factory ammo can be faulty at times. If the chamber was too tight all the ammo would stick. |
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You said an "unfired cartidge" will get stuck? I've only dealt with Bushy's and mil issue, but I would also check the bullet for signs of having engaged the rifling. Like the previous poster said, a drop test of ammo in the chamber should tell you a little bit. Can you push the bolt carrier and lock the bolt (hinged open) using finger pressure only?
Some guys will say that polishing a chamber will decrease the friction between the case and chamber upon firing and increase the pressure exerted on the bolt...probably not an issue, but on a high dollar barrel I'd be tempted to send it back. |
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If you want to try a little heavier polish job, try this: pick up one of YOUR fired cases FROM THE RIFLE YOU WANT TO POLISH. Now you have a polishing tool perfectly sized to your chamber, made from soft brass that will not hurt it. Knock out the primer, and screw a sheetmetal screw into the primer pocket, and clip off the head. Use a crimp on wire connecter(I like the big yellow ones) from an automotive wiring set, and then find a piece of heavy wire or light rod long enough to clear the reciever, and crimp it into the other end of the connecter.I like this piece to be flexible so that you don't inadvertently apply pressure to one side of the chamber. A flexible piece lets the brass run freely in the chamber Chuck it in your drill, or if that makes you nervous, do it by hand. Put on some flitz, or polishing compound, or JB paste and run it in. Polish the chamber up to a mirror shine. This will really slick up you chamber without taking off metal, and if you have any burrs the should show themselves on the brass case. If you really wanted to open it up a little, you could put on a fine valve grinding compound, but remember it's really hard to put metal back in the chamber once you take it out. A good cleaning after, and go light on the compound so it doesn't get flung all up in the extension recesses. If you have a piece of rubber hose handy, cut it the length of the rod and slip it over to protect the inside of your reciever in case anything "gets away from you".
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| No, its not a good idea to shoot it more until the problem is figured out, or keep messing with chamber polish. As someone pointed out the ammo also could be too long in length or as I stated it may not be sized correct by the factory. You should hand chamber test all your ammo before you load it into your mags to see if any of it is a problem. If it sticks or doesnt push all the way in and then come out easily those rounds should not be used. Some companies like JP sell a device that checks you ammo for size and its a good item to have even for factory ammo. Shooting a rifle in with a problem like this could end with a blown case.. |
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1 in 7: Thank you for your feedback. I do understand the potential danger with this probelm. Given that it occurs overwhelmingly with LC 55 grain, I'm inclined to believe it's the ammo. Funny thing is this same ammo fucntions perfectly in other rifles.
Could it be a headspace problem? |
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Quoted:
1 in 7: Thank you for your feedback. I do understand the potential danger with this probelm. Given that it occurs overwhelmingly with LC 55 grain, I'm inclined to believe it's the ammo. Funny thing is this same ammo fucntions perfectly in other rifles. Could it be a headspace problem?[/quote] We've got a winner!!! Not a problem, an ISSUE. A cartridge/chamber headspace relationship issue. You can change the cartridge or you can change the chamber. Try some different ammo. If you have a reloading buddy that has the proper equipment, you can measure the AMMO headspace. OR separate upper from lower Or, you could take the extractor and ejector out of your BCG, reassemble complete with FP to hold everything together, and see if it will close without resistance. If you have to really slam the BCG home to get it to lockup on the empty round, then the ammo/chamber headspace is TOO LONG. If it closes with no pressure, then it is fine. –––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––– Also, the super mondo heavy duty black extractor springs and black rubber O-rings that everyone thinks they have to have for the gun to run right, TEND to cause this to an extent. There is SOOOO much extractor tension, that it takes an extremely high amount of force to get the extractor to snap over the rim of the cartridge. This jams the loaded round into the front of the chamber a correspondingly forceful amount. It gets wedged in the chamber. >> kinda like that. You can run one or the other, but the extremely high extractor tension is a Band-Aid for a configuration that is way out of time anyways. The front face of the extractor does tend to get polished over time as well too. so get try different ammo, or polish whatever you want, it is your gun, but since you state that the gun tends to run without hiccup, and you aren't in a life or death situation, I would JUST SHOOT IT!!! My two cents, or a penny for your thoughts. Brett |
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Quoted:
If you want to try a little heavier polish job, try this: pick up one of YOUR fired cases FROM THE RIFLE YOU WANT TO POLISH. Now you have a polishing tool perfectly sized to your chamber, made from soft brass that will not hurt it. Knock out the primer, and screw a sheetmetal screw into the primer pocket, and clip off the head. Use a crimp on wire connecter(I like the big yellow ones) from an automotive wiring set, and then find a piece of heavy wire or light rod long enough to clear the reciever, and crimp it into the other end of the connecter.I like this piece to be flexible so that you don't inadvertently apply pressure to one side of the chamber. A flexible piece lets the brass run freely in the chamber Chuck it in your drill, or if that makes you nervous, do it by hand. Put on some flitz, or polishing compound, or JB paste and run it in. Polish the chamber up to a mirror shine. This will really slick up you chamber without taking off metal, and if you have any burrs the should show themselves on the brass case. If you really wanted to open it up a little, you could put on a fine valve grinding compound, but remember it's really hard to put metal back in the chamber once you take it out. A good cleaning after, and go light on the compound so it doesn't get flung all up in the extension recesses. If you have a piece of rubber hose handy, cut it the length of the rod and slip it over to protect the inside of your reciever in case anything "gets away from you". Quoted for awesomeness. Excellent idea for new barrels that have roughness in the chambers.  Brett
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