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Posted: 4/20/2009 7:22:22 PM EDT
| Im kind of new to the ar 15 world but read as much as I can about them. I put two of them together during the winter and just fired one of them this weekend. The one I fired has a RRA lower and the rest is Double Star. I put 30 rounds into a mag fired and had no problem firing. What I did have a problem with was to pull the charging handle each time to eject the case out and reload a new round. Could anyone tell me why my ar is acting bolt action. Any feedback would help. Thanks |
| Its a gas problem..is there carbon blowing back into the upper everytime you manualy cycle it? if so then gas is coming through the tube but not cycling the carrier could be the carrier key.Check and see that the gas tube is straight and before you retourque the key screws take it off completely and make sure theres nothing in the key or carrier gas hole.Is the gas tube upside down..yes ive seen this happen and from a factory rifle.One things for sure theres a gas problem.What type of barrel and did you play around with the FSB in any way..FSB pinned or adjustable gas block? |
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Great staking info:
http://www.ar15.com/forums/topic.html?b=2&f=130&t=160446 |
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I've seen many problem many times. The majority of the time it is a gas block alignment issue or too small of a gas port hole issue. What you need to check or if you already looked while shooting is, does your bolt carrier move back when shooting. If it moves back just not all the way, then first check issues such as buffer, buffer spring, making sure your upper receiver, charging handle and BCG are all lubed properly. Make sure that when you pull on the charging handle that there is a smooth sliding action, make sure that when your bolt matches up with the chamber that there is no friction and it's all a smooth action. IF all that works fine, then it's time to tear gas block down. remove whatever you need to, to check the gas port hole and look at the carbon blow out to see if your hole was completely covered when the gas block was over it. blow into the end of your gas tube to make sure that air is able to flow freely through the tube through out the gas block.
Now if the gas whole was not completely covered make sure that you adjust accordingly, re-install and test fire. You can contact me if you still run into issues and i'll do what i can to help. [email protected] |
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Quoted:
took apart the whole bolt carrier and everything seems to be in working order. The 2 allen key bolts for the gas tube were very easy to take off so I tighted them up a little more. The 3 o-rings felt fine when I took them out. Im stumped! A slightly misaligned gas block on the barrel can cause this type of problem. Also, make sure your gas tube retaining pin is placed properly into the gas tube. I've had one fall out and turn an AR into a bolt action. As others have said, you need to make sure that the tube is in right side up as well so that the gas port to the tube is able to receive the gas and direct it rearward. If you have tightend the gas key you may as well make sure you stake it according to the link that was posted above to prevent the bolts from backing out oon their own in the future. |
| Thanks for all your feedback. To answer some questions the chamber is and was clean never fired and the gun is and was properly lubed. Pulling back on the charging handle everything went smooth loaded up a round fired it and the bolt carrier did not budge. The barrel is a 16” 1x9 crowned chromemoly match barrel w/ M-4 cut made by Double Star. Bought it as a complete at a gun show. I guess I'll just have to do trial and error and play around with the gas tube being that thats what most people are pointing there fingers at and refer to the previous thread on how to align. Ill post most pics soon so you can get a better idea. Thanks again for all your help. |
| I'm reminded of a post I saw on this site a few years back. I'm not sure how, but someone had managed to install a gas tube upside down on his piece. You might want to check that possiblity befor tearing everything apart. If nothing else, it'll show you if any gas is getting to the tube. since in todays aftermarket it's always possible you got a barrel w/o a gas port. |
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Don't know if you have access to compressed air, but if you can cork off one end of the barrel and insert a blow gun w/ rubber tip at the other and pressurize the barrel you should hear/feel air coming out the gas tube, you do NOT, that is your problem.
Gas blocks can be installed mis-aligned and cover the gas port, barrel could have the gas port drilled to the incorrect diameter and thus short stroking and NOT extracting/loading the next round, there could be some fouling in the port or tube, etc. Preservative or some substance used during manufacturing/assembly got into the port/tube and fouling it? Eitherway, if the bolt does NOT move at all gas is NOT getting to the BCG. If the bolt moves but NOT enough to feed/extract, you've got a gas problem. |
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if your bolt stays open after each firing its not your gas tube, if it fires but doesnt eject the case and / or your bolt isnt moving at all right after firing its your gas system., check and make sure your front sight base or gas block is sitting in the right spot. Really easy to do. . there is a small hole on top of your barrel that your gas block or front sight base sits on top of. its a small hole, if it gets misaligned you wont get enough gas down your gas tube to cycle your bolt back. If you get lost and need help txt msg me and i might be able to help. Read the links below and you"ll be good to go!!!
http://www.varminthunters.com/ar15tech/freefloat/ar15freefloat.html http://yankeehillmachine.com/store/media/4Rail_LoPro_SingleGB.pdf http://yankeehillmachine.com/store/media/2_pc_GasBlocks.pdf |
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Just an update. I plugged up the bolt end of the barrel and forced air through front of the barrel and got nothing to come out of the gas tube. So Im going to take everything apart and rebuild someone elses mistake.
*Update* After taking almost everything apart I found that whoever built the upper never fully put the gas tube into the block. I pulled out the retaining pin and was still able to push the gas tube into the block another 1/4". Put everything back together and again forced air through the front of the barrel and SUCCESS! Air came through the tube and out to where the bolt carrier was supposed to be. Even plugged up the tube to see if I had any leaks and nothing. Only thing that happened was me almost passing out. Thanks again guys for all your help you have been GREAT!! |
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