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Posted: 3/8/2010 8:27:20 AM EDT
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Is there a fix for distortion of the buffer pin hole?
My Colt AR 223 has this problem. Some time ago, 2 years or more ago I replaced the buffer and spring with Tubb parts. What I didn't notice was that the buffer pin was banging the front part of the hole the pin lives in. Then ultimately, the pin and spring came out and took up residence with the trigger unit. I simply removed the pin and spring and used the rifle without. I haven't shot the rifle for over a year and had forgotten about this problem. Last Thursday after cleaning, I replaced the pin and spring; Reassembled the rifle and went to the range last Friday. The first round out the barrel reminded me that there was a problem. I opened it up and the pin was in front of the hammer and the spring was on the side. I looked closely at the pin retainer hole and saw that there was some material either distorted badly or actually removed, but with the same effect. The pin is pushed forward and pops out of the hole and goes down into the lower and causes problems. Is there a fix for this? Can the hole be drilled out and a larger pin inserted? Or can the hole be drilled out oversized and a steel sleeve be pressed in and then the pin and spring be inserted? Any help is appreciated. Roy |
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Without a reference photo to gauge how badly the hole is distorted, it's hard to say.
First things, first (and this is not meant to insult your intelligence), but are you certain that the buffer tube is threaded into the receiver to it's appropriate depth at this point in time? There is a point where one revolution of the tube allows it to make contact with the retainer pin, but another full revolution can be achieved to make postive capture of the pin without the tube being inserted too far and binding. In all of mine, the extension tube's threaded end is very nearly flush with the nipple of the pin - not just covering the rim of the flange at the base of the nipple. I'd check that before proceeding. If you're using the same retainer pin, you might compare/replace it with a known-good pin and ensure that it's not a too-small-pin versus a too-big-hole. Failing that, an easy fix (and one I would probably go with) would be to remove the buffer tube, carefully file down the threaded end until it reaches a length which will allow it to complete another full revolution into the receiver and maintain the pin securely in it's seat. Take off a very small amount with a few passes of a hand file until you reach the ideal amount of contact. If the problem is with the hardening of the receiver, then you may just end up with a more badly deformed hole - but I would think that with the amount of force being exerted that this shouldn't be an issue. I'd actually expect the pin itself to be destroyed long before the receiver is damaged... If you get a chance, shoot a pic. I'd like to see the damage - It's not an issue I've ever encountered or even considered but would be interesting to see... ETA: I managed to work in the phrases "rim", "nipple", "hardening", "too-small-pin" and "too-big-hole" in a tech thread. My advice may be shit - but my unintentionally explicit ninja skills are superb... |
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Quoted:
Primary Weapons Systems has a buffer tube with a shelf built into it that would hold your pin, if I am understanding your problem correctly. One of my guns has a tube with a little notch for the BRP. If you depress the pin, the tube will turn about one more thread and line up perfectly. The pin pops back up into the notch without binding. It was manufactured that way but it doesn't look like something you couldn't do in about three minutes with a small round file. If the hole in the receiver is egged out, I'll bet you could drill it out oversized and thread or affix a sleeve of some kind. Maybe just weld it full and redrill the hole to spec. It's not really a complicated component, it's just a hole. |
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Don't know if this will help cuz things seem to be changing. No one contacts the Mfg. prior to posting anymore? Bad call
http://www.biggerhammer.net/ar15/cad/ 458 |
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Quoted:
Without a reference photo to gauge how badly the hole is distorted, it's hard to say. First things, first (and this is not meant to insult your intelligence), but are you certain that the buffer tube is threaded into the receiver to it's appropriate depth at this point in time? There is a point where one revolution of the tube allows it to make contact with the retainer pin, but another full revolution can be achieved to make postive capture of the pin without the tube being inserted too far and binding. In all of mine, the extension tube's threaded end is very nearly flush with the nipple of the pin - not just covering the rim of the flange at the base of the nipple. I'd check that before proceeding. If you're using the same retainer pin, you might compare/replace it with a known-good pin and ensure that it's not a too-small-pin versus a too-big-hole. Failing that, an easy fix (and one I would probably go with) would be to remove the buffer tube, carefully file down the threaded end until it reaches a length which will allow it to complete another full revolution into the receiver and maintain the pin securely in it's seat. Take off a very small amount with a few passes of a hand file until you reach the ideal amount of contact. If the problem is with the hardening of the receiver, then you may just end up with a more badly deformed hole - but I would think that with the amount of force being exerted that this shouldn't be an issue. I'd actually expect the pin itself to be destroyed long before the receiver is damaged... If you get a chance, shoot a pic. I'd like to see the damage - It's not an issue I've ever encountered or even considered but would be interesting to see... ETA: I managed to work in the phrases "rim", "nipple", "hardening", "too-small-pin" and "too-big-hole" in a tech thread. My advice may be shit - but my unintentionally explicit ninja skills are superb... job well done. to the OP, the above advice is on the money. |
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Just for your information.
The retainer pin hole is badly battered on the front end at the top of the hole. Not a lot, but it allows the pin to pop out into the lower and blocks the trigger. I'll try to get photos soon. I just got out of the hospital getting an angioplasty and still a bit goofy. Roy |
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