Posted: 7/23/2010 3:20:52 PM EDT
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Hey Guys,
I have run into a problem with the LAR-8 and was wondering if anybody has had a similar problem. I have a LAR-8 midlength with a 16" barrel that has the rifle extension buffer tube. I have had it for a year and it funtions great. I got a brand new in the box LAR-8 standard 20" barrel that will not function properly. The rifle has the rifle extension buffer tube. The standard will not lock the bolt to the rear. I swapped the out the buffer and spring from the midlength to the standard and it functions properly. I put the standard buffer and spring in the midlength and it will not lock to the rear. The midlength buffer and spring are carbine buffer and spring while the standard are rifle buffer and spring. I took the rifle to my local gunsmith. He called Rock River and explained the situation to them. They said the standard buffer and spring are the correct ones. They do not understand why the standard is behaving like this while the midlength is functioning properly in both rifles. In order to keep sending the rifle back to Rock River and not seeing it for six months, Rock River is sending a carbine buffer and sping to order for the standard to function properly. So be on the lookout for this problem and chime in with those problems similar to mine. kingwolf |
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Are you talking about the bolt not staying open after you shoot a magazine through it? Or if you push the bolt release? I have a 20" LAR-8 I havent had any problems with the bolt staying open. I will get mine out and see if i can get it to replicate the problem. Let me know what you find out.
Thanks |
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MJRettick4,
The problem I am having with the 20" rifle is when I pull the charging handle back, the bolt is not traveling back far enough to engage the bolt open latch even holding the latch to engage the bolt. It works with the buffer and spring from the 16" but not the buffer and spring it came with. Could it be I have a 20" rifle setup with a midlength gas system? |
| This is kind of a no brainer question but did you see if there was anything in the back of the of the buffer tube? Maybe something was stuck back there during assembly. Can you take a measurement of your buffer and spring? When I get home this morning I will take mine out and measure mine and post them up for you. |
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Hey guys,
The buffer tube on both rifles is the rifle extension buffer tube. I looked at the the standard buffer tube and there was nothing in the bottom of it. The gunsmith also loolked at the buffer tube for a second set of eyes and could see nothing. I am scratching my head over this one as well as the gunsmith. MJRettick4, when you post your measurements, could you send pictures also? Both of my rifles are currently at the gunsmith to have goodies installed on them and get this bolt not locking to the rear problem solved. Thanks for you help in this matter guys. kingwolf |
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If you have the same extension on both, you should have the same buffer and spring as well. The CAR-tube on the LAR-8 is longer than a regular (.223 platform) CAR extension, but shorter (inside length) than the rifle extension ansd uses a .308 LAR-8 specific CAR spring and buffer, which are different from the spring and buffer used in the rifle-length extension.
Please clarify which extensions (and stocks if you would) you have on the two different rifles, as use of the shorter LAR-8 CAR spring and buffer in the rifle-length extension is not correct and can cause significant other issues and is NOT to be attempted. You can either do so here, or contact me at RRA (866-980-7625, ask for Steve) Thanks. Steve/RRA |
| I also have an A4 20 inch lar 8 that will not hold the bolt open after the last shot. I have tried it with 5 different magazines and its a no go . I can take the upper off and see the magazine push the bolt hold open device up and when the upper is on the gun I can pull the handle back and make it work , It just wont hold open on the last shot and I have used winchester white boc 147 grain , federal fusion 150 grain and federal 180 grain ammo. . the rifle has been flawless as far as feeding and extraction I have no complaints there I would just like it to hold open on the last shot. |
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Yes.
The accepted safety standard for any AR style rifle is that you never throw a round in through the ejection port or worse, push it into the chamber by hand. You ALWAYS fire form a magazine, or a magazine with a single shot folower, or from something like a BobSled. Rememebr those dimples you have on the primer if you eject a live round? That's caused by the floating firing pin 's forward momentum. When loading from a mag, the process is slowed, some of that momentum is gone, and the round is in the same location on each pass of the carrier. The ejector can get around th erim, and it functions like it was designed. A loose round and no mag can very possibly produce a slam fire as that firing pin "does its thing" while the ejector is trying to get over the rim of the round while the round itself isn't physically where it's supposed to be at that point in a process that takes a coupel of micro-seconds. That holds true with any AR rifle, but the large platform models are more prone to it with the much greater mass of the carriers. Steve/RRA |