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Posted: 10/25/2011 8:43:42 AM EDT
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I have a 6920 and the edge of the buffer face is marked up all the way around the edge. I suspect the buffer is making contact with the pin. Is this an issue that should be corrected? If so, how do you correct it? I believe that when you close the upper and lower the rear of the carrier does not push back the buffer a bit like it should.
I suppose repeated contact could egg out the retaining pin hole and I'd rather that not happen. How do I remedy this? |
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Quoted:
I have a 6920 and the edge of the buffer face is marked up all the way around the edge. I suspect the buffer is making contact with the pin. Is this an issue that should be corrected? If so, how do you correct it? I believe that when you close the upper and lower the rear of the carrier does not push back the buffer a bit like it should. I suppose repeated contact could egg out the retaining pin hole and I'd rather that not happen. How do I remedy this? Find out if the rear of the carrier is hitting your buffer. If you are not pushing the face of the buffer a smidge, there is something wrong. Is the entire carbine Colt? Quick fix is to put a spacer in the rear of the extension, then install the spring and buffer. Does not have to be that thick, something like the twang buster. Pics would be good. |
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Quoted:
All is Colt except the carrier which I believe is a Smith Enterprises. Doesn't have any markings on it. I would look to see if the rear of the carrier to see if it is smooth. Also, try a different carrier. The bolt carrier should push the buffer back out of contact with the pin, as you close the two halves. Quoted:
Won't a spacer just push the buffer against the pin even more? I was thinking that the bolt carrier was coming back too far because the inside of the extension tube was too long, sorry. The M16 Clinic pad is a band aid if the buffer is hitting the pin. Post pics. |
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Sounds like the carrier is a hair too short. The carrier should relieve the pressure from the retaining pin when the rifle is closed, the pin is only there to retain the buffer while cleaning/maintaining the rifle.
I don't understand why anyone would replace a known good BCG (in this case the gold standard of BCGs) with a gimmick unit like a Smith or Fail-often. |
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As stated, you have one or more of these problems.
Buffer retaining pin channel was milled too far forward in the receiver, the B/C was milled too short, the barrel extension socket was milled too long (face of barrel extension not flush with the front of the receiver, and/or, the bottom slot on the carrier not milled correctly as well. Photo's and measurements of all would help us get to the bottom of the problem quickly. |
| How dirty is it when you shoot it. I have seen this on alot of M16s, but they have have had thousands of rounds in them, caused by the back of the b/c smashing the the buffer face and making a silver ring all the way around the buffer. But they have been shot full of sand and dirt... |
| Some carriers actually have machining rings on the face that contacts the buffer. That plus the coating can cause the marking on the buffer. I take my carriers and remove any machining marks, use fine stones, very fine wet/dry sandpaper, then lightly round edges and finally polish to a mirror finish on a hard felt buffing wheel mounted on a grinder stand, using a very fine polishing compound. After doing this I have had no more erosion of buffer faces. |
| I had this on an AR45 receiver. Khalan Arms. It had lots of such mistakes. The retainer hole was too far back and yes the hole got egged out. You could see the receiver extension threads deforming. I took the buffer to a machine shop and they put it in a lather and took a bit of metal off all the way around the edge of the buffer face. Worked fine after that. |
Here's a side by side of a buffer machined to clear the buffer detent with an out of spec detent hole (left), and the original buffer after about 1K rounds of it hitting the pin (right). You can see the inner ring of normal carrier wear on the righthand buffer. This buffer was probably way too soft, but then again, that might have saved the detent pin.
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