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Old 11-12-2010, 03:38 PM   #11
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I would almost think that the spring pushing the detent into the rear take down pin may be the issue, or possibly the detent itself. The Accuwedge may put enough lateral pressure on the pin to half way keep it in place during firing, but it isn't the real solution. There has to be one of three components causing the problem, and all are inexpensive. The pin, the detent, and/or the spring. I don't know that I would take the time to try am diagnose the problem as opposed to going to the gun store with ten bucks, and replace all three components. Maybe score an Accuwedge while I was there. Just my .02$

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Old 11-12-2010, 03:48 PM   #12
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I think Double S is talking about this:




What is curious to me is that Jpyle says that the pin rattles and allows the upper receiver to separate from the lower. That makes it sound like the pin isn't large enough for the hole in the upper. With added pressure forward, from the detent towards the fire control group, it would help, but why is there so much extra play??

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Old 11-12-2010, 03:52 PM   #13
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OK, I think I follow you J.D. The only real way to get all of this straightened out would be to use a small hole guage and measure the i.d. of the hole in the upper, the two holes in the lower, and then use a mic or a caliper and measure the o.d. of the take down pin. The differences of all of the measurements should be about .005" of an inch I would think. But then Pyle stated what sounded to me like the take down pin can rattle all of the way out? I guess we should wait for some pictures or more details.

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Old 11-12-2010, 04:13 PM   #14
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No, you brought up a good point S.S. Good for you thinking outside the box.

I agree it would be easy to shotgun the whole thing and fix the problem, but from my aspect, as Jpyle has an upper that I sold him, I am curious as to whether there is a problem with the receiver or with the pin.

I know the receiver is not a large pin Colt type, it an Olympic Arms model, but I don't know about the lower he ended up with. The DPMS parts kit referenced above, if he bought that one, should be standard.

Those pins SHOULD be about .153" or .154" in diameter and should fit both the lower and the upper without a problem.

I am curious to see the pics as we are just guessing at this point, but I know that Jpyle is pretty good about being able to grasp the finer points, so I know it's just not him with some funky bargain bin part.

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Old 11-12-2010, 04:19 PM   #15
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He stated earlier in the thread he ended up with a Yankee Hill Machine lower, so that ought to be the small hole take down pin type. I am leaning towards something being up with the parts kit or maybe one spring switched around. But you are right, it's all conjecture at this point.

Just talking about this, and you're AR10 thread makes me want to build another rifle. I need a better paying job just to hang out with you guys online. Sigh.

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Old 11-12-2010, 10:52 PM   #16
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Default The plot thickens...

So I go out at lunch to pick up a new take down pin and a caliper determined to figure out why the installed pin won't hold. When I get home I look over the lower and eyeball the fit of the pin to the holes on both sides, very little clearance, pin completely obscures hole, no binding on either side...ok cool not a spec problem with the lower but I'll use the new digital caliper to measure both holes, front and back just in case...loosen the stock screw, slide it off, ease out the spring, now the detent...? Where the hell is the damn detent, I know I put it in there, didn't have any parts left over. Searched for over an hour, that little sucker is nowhere to be found...friggin gremlin took it.

So one mystery is solved and another arises...now I have to pay $8 in shipping on a $.02 part. Gonna order a dozen and springs to boot.

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Old 11-12-2010, 10:54 PM   #17
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You mean to tell me you don't have a single store there in NJ that sells black rifle parts??? I can score that detent at my local shop for free!!!

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Old 11-12-2010, 10:59 PM   #18
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Quote:
Originally Posted by Squirrel_Slayer View Post
You mean to tell me you don't have a single store there in NJ that sells black rifle parts??? I can score that detent at my local shop for free!!!
Not a one...I had to get the lower online and the LPK and stock in Delaware. No one in NJ believes you can even own an AR and most gun shops do not stock parts...especially AR parts. I went to seven different shops in 3 different counties looking for parts and people looked at me like I was nuts for even asking.

I'm going to order a few more mags anyway so I'll just put a field kit of emergency repair parts together...
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"A free people ought not only to be armed and disciplined, but they should have sufficient arms and ammunition to maintain a status of independence from any who might attempt to abuse them, which would include their own government." - George Washington


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Old 11-12-2010, 11:06 PM   #19
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bummer! I can try an go get you some and mail it to you in an envelope, cost me a whopping .44$.

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Old 11-12-2010, 11:09 PM   #20
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JP - Well I hope this fixes the problem. I am happy to hear that the pin itself appears to not be the problem, which means the upper I sent you wasn't out of spec.

I knew the thing didn't have a ton of time or rounds through it, but I honestly never thought to check if the pin holes had been worn out from constant take down and assembly.


The offer still stands, if you need anything, let me know as I want to make sure you got what you paid for.

JD

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