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Posted: 1/25/2016 3:54:34 PM EST
[#1]
EDIT: I was wrong. This is a carrier burr issue.
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Posted: 1/25/2016 3:54:56 PM EST
[#2]
I got one doing that also.
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Posted: 1/25/2016 4:08:02 PM EST
[#3]
I would buy a new one just to make sure the issue has not continued. At minimum, I'd put some sharpie or dykum on the buffer face to see if new indentations appear. Also, make sure there are no burrs present on the outer diameter of the buffer that might scour the inside of your buffer tube.
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Posted: 1/25/2016 4:10:26 PM EST
[#4]
The damage is from the buffer hitting and resting on the retainer pin instead of the rear of the bolt carrier.
Probably because the hole for the buffer retainer pin is drill too far back towards the rear of the lower receiver. Is this a 80% Lower Receiver? Did you drill the buffer retainer pin hole? If it's a commercial Lower, I'd return it to the Manufacturer for replacement as a manufacturing defect. There isn't any easy way to fix the problem. |
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Posted: 1/25/2016 4:21:09 PM EST
[#5]
Quote HistoryQuoted:
The damage is from the buffer hitting and resting on the retainer pin instead of the rear of the bolt carrier. Probably because the hole for the buffer retainer pin is drill too far back towards the rear of the lower receiver. Is this a 80% Lower Receiver? Did you drill the buffer retainer pin hole? If it's a commercial Lower, I'd return it to the Manufacturer for replacement as a manufacturing defect. There isn't any easy way to fix the problem. This is a commercial lower. |
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Posted: 1/25/2016 4:24:24 PM EST
[#6]
when you close the reciever, the carrier should push the buffer back a tad
my Mag lower has the same issue, due to an out of spec buffer retension pin location DSA buffer loc might fix this |
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Posted: 1/25/2016 4:40:36 PM EST
[#7]
It would be highly unusual for the buffer to be able to contact the retaining pin with the action closed. If it did, it would break the little pin off pretty quick. The scratches on the face of the buffer are from sharp edges on the lower edges of the bolt carrier. The bolt carrier pushes the buffer back away from the retaining pin when you close the action, so there's no way the buffer can contact the pin again until the action is opened and the bolt carrier is out of the way. You can test this yourself by observing the face of the buffer as you close the upper and see the bolt carrier pushing the buffer back as it closes.
Plus, if the buffer were to strike the pin hard enough to make those marks (which can't be made by the pin in the first place since it's round), the pin would be broken off immediately. It's much more likely that there is an anomaly on the rear of the bolt carrier. We already know that the lower corners of the BC should be stoned to eliminate the scratching. Perhaps there's something else there that could be causing the marks? |
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Posted: 1/25/2016 4:48:43 PM EST
[#8]
check for a burr on the rear of the bolt carrier
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Posted: 1/25/2016 4:49:17 PM EST
[#9]
The buffer retention pin hole is likely too rearward.
It's allowing the buffer to come into contact with the retention pin. This will eventually lead to a broken lower once fired/cycled enough. I had this same problem with a lower several years back. |
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Posted: 1/25/2016 4:49:43 PM EST
[#10]
Check the tail of the carrier where it's bottom channel cuts are. I bet it's flared/burred slightly. If it is, file off the bad edges and blue those spots.
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Posted: 1/25/2016 5:05:53 PM EST
[#11]
There is a burr on your bolt carrier, probably near the retainer pin slot. You can smooth it out with sandpaper or Dremel.
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Posted: 1/25/2016 5:10:37 PM EST
[#12]
Buffer retention pin hole is drilled to far back, or carrier is short.
Ryan |
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Posted: 1/25/2016 5:11:10 PM EST
[#13]
Quote HistoryQuoted: It would be highly unusual for the buffer to be able to contact the retaining pin with the action closed. If it did, it would break the little pin off pretty quick. The scratches on the face of the buffer are from sharp edges on the lower edges of the bolt carrier. The bolt carrier pushes the buffer back away from the retaining pin when you close the action, so there's no way the buffer can contact the pin again until the action is opened and the bolt carrier is out of the way. You can test this yourself by observing the face of the buffer as you close the upper and see the bolt carrier pushing the buffer back as it closes. Plus, if the buffer were to strike the pin hard enough to make those marks (which can't be made by the pin in the first place since it's round), the pin would be broken off immediately. It's much more likely that there is an anomaly on the rear of the bolt carrier. We already know that the lower corners of the BC should be stoned to eliminate the scratching. Perhaps there's something else there that could be causing the marks? |
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Posted: 1/25/2016 5:15:09 PM EST
[#14]
If the buffer retainer is the issue this would probably fix it, $15
http://commonbullets.com/wp/archives/1727 |
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Posted: 1/25/2016 5:18:21 PM EST
[#15]
A picture taken from the top of the lower over the retention pin area would clear this up quickly.
That said, even analyzing the two pics already provided, the buffer does not appear to be protruding out of the receiver extension/lower enough to be depressed by the carrier. It's a tricky angle in the pic to know for sure, but it looks like an out of spec buffer retention pin hole to me. |
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Posted: 1/25/2016 5:27:42 PM EST
[#16]
Look at the back of your carrier, I think you'll find that it has burrs that are causing that damage.
No way the pin would hold up to 1100 rounds |
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Posted: 1/25/2016 5:30:18 PM EST
[#17]
Upon further review, I'm in the "burr on the bolt carrier" camp. The scratches that begin toward the center of the buffer were likely caused while closing the upper.
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Posted: 1/25/2016 5:30:55 PM EST
[#18]
Looks to me like the rear of your carrier where the pin ride channel is machined may have some sharp edges sticking out in the rear.
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Posted: 1/25/2016 5:33:32 PM EST
[#19]
It's a burr or peened edge on the rear of your carrier. I have one that does similar for this reason. Post a good pic of the rear surface of your carrier.
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Posted: 1/25/2016 5:40:57 PM EST
[#20]
 The buffer moves slightly rear as I close the upper.
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Posted: 1/25/2016 5:42:59 PM EST
[#21]
Its from the carrier. Feel the edges and smooth it out.
Come on guys you really think that a round buffer retainer could leave those marks?  Not to mention the buffer retainer will bend a shear clean off after 2-3 strikes of the buffer ramming it under the full pressure of the spring. |
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Posted: 1/25/2016 5:44:05 PM EST
[#22]
Quote HistoryQuoted:
Its from the carrier. Feel the edges and smooth it out. Come on guys you really think that a round buffer retainer could leave those marks?
Not to mention the buffer retainer will bend a shear clean off after 2-3 strikes of the buffer ramming it under the full pressure of the spring. Finally, something we can agree on. 
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Posted: 1/25/2016 6:00:11 PM EST
[#23]
Quote HistoryQuoted: If the buffer retainer is the issue this would probably fix it, $15 http://commonbullets.com/wp/archives/1727 i ordered one thanks! |
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Posted: 1/25/2016 6:02:27 PM EST
[#24]
the acid test would be to clean up the buffer face and pull the retainer pin and spring out
it makes shotgunning the reciever open tricky, but you don't have to keep the retainer to run an AR |
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Posted: 1/25/2016 6:04:52 PM EST
[#25]
Quote HistoryQuoted:
<a href="http://s163.photobucket.com/user/yosarian_2007/media/IMG_0502.jpg.html" target="_blank">http://i163.photobucket.com/albums/t286/yosarian_2007/IMG_0502.jpg</a> The buffer moves slightly rear as I close the upper. It's the carrier for sure. |
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Posted: 1/25/2016 6:08:37 PM EST
[#26]
Quote HistoryQuoted:
Its from the carrier. Feel the edges and smooth it out. Come on guys you really think that a round buffer retainer could leave those marks?
Not to mention the buffer retainer will bend a shear clean off after 2-3 strikes of the buffer ramming it under the full pressure of the spring. Got over 500 rounds through my Seekins lower before noticing my buffer retention pin hole was out of spec. Buffer looked very similar to this one. The rear walls of the lower were visibly showing wear and impending doom to the receiver itself, but I put quite a few rounds down range with it still functional. |
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Posted: 1/25/2016 6:33:23 PM EST
[#27]
Is that a steel buffer? The back of the carrier must be gnarly to cause that damage. While you are in the pic posting mood, post some pics of the back of the carrier where it would contact the buffer. How would a bur on the carrier cause the marks in the middle of the buffer?
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Posted: 1/25/2016 6:37:24 PM EST
[#28]
It's 100% a burr/ sharp edges on your carrier tail. You can tell by the scratches the run from the center of the buffer to the rim of the buffer. These scratches are caused when you close the lower receiver on the upper receiver. Once closed and you fire the rifle, that burr only hammers the rim area of the buffer.
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Posted: 1/25/2016 6:47:07 PM EST
[#29]
Quote HistoryQuoted: Is that a steel buffer? The back of the carrier must be gnarly to cause that damage. While you are in the pic posting mood, post some pics of the back of the carrier where it would contact the buffer. How would a bur on the carrier cause the marks in the middle of the buffer? It's likely a single burr, the size and shape of one of the single indents you see on the buffer. The "clockwork" markings that go around the circumference but all look similar are from the same burr, or maybe two. The buffer rotates a bit during operation, so after a while you get those marks all around. The scratches in the center of the buffer are more irregular and less numerous. Those are from the occasional time when the receiver was "shotgunned" open and the same burr on the carrier dragged across the diameter of the buffer as the upper receiver tilted up, and then again when it was closed. |
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Posted: 1/28/2016 8:09:49 PM EST
[#30]
Quote HistoryQuoted: i ordered one thanks! Quote HistoryQuoted: Quoted: If the buffer retainer is the issue this would probably fix it, $15 http://commonbullets.com/wp/archives/1727 i ordered one thanks! it came in today, pix to come |
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Posted: 1/28/2016 8:45:07 PM EST
[#31]
Quoted:
<a href="http://s163.photobucket.com/user/yosarian_2007/media/IMG_0497%201.jpg.html" target="_blank">http://i163.photobucket.com/albums/t286/yosarian_2007/IMG_0497%201.jpg</a>" target="_blank"><a href="http://s163.photobucket.com/user/yosarian_2007/media/IMG_0497%201.jpg.html" target="_blank">http://i163.photobucket.com/albums/t286/yosarian_2007/IMG_0497%201.jpg</a></a> My rifle has fired 1160 rounds. The rifle functions %100 but the wear marks do not look normal. I swapped out uppers at the 890 round mark. Should I buy a new buffer or keep shooting with this one? I have checked the new bcg and it has no burrs so this could have been done with the old bcg. This is from a burr on the bolt carrier. If you look at your pics, the height of the marks are longer than the contact height of the pin. A round retainer pin can not make a sharp mark like you have on the buffer. |
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Posted: 1/28/2016 10:19:50 PM EST
[#32]
 here is my MAG lower with the stock pin  here is the edge damage from the buffer pin strikes, the old pin and the new offset pin When closed, the carrier did not touch the buffer face  offset pin installed  now the buffer is about an eighth of an inch further out and the carrier pushes the buffer back when the upper is closed |
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Posted: 1/28/2016 10:39:42 PM EST
[#33]
Cool, thanks for the pics and update. Looks like it should take care of your issue. Looking at your buffer compared to the OP's is does appear that his carrier is to blame.
Quote HistoryQuoted:
http://www.googlepixel.com/images/buffer1.jpghere is my MAG lower with the stock pin http://www.googlepixel.com/images/buffer2.jpg here is the edge damage from the buffer pin strikes, the old pin and the new offset pin When closed, the carrier did not touch the buffer face http://www.googlepixel.com/images/buffer3.jpg offset pin installed http://www.googlepixel.com/images/buffer4.jpg now the buffer is about an eighth of an inch further out and the carrier pushes the buffer back when the upper is closed |
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Posted: 1/29/2016 1:21:35 AM EST
[#34]
Wet stone the ass end of your carrier. It'll stop.
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Posted: 1/29/2016 11:56:12 AM EST
[#35]
Yes my bolt carrier has a small burr . Going to take care of it this weekend. Thank you for the help .
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Posted: 1/30/2016 9:37:02 AM EST
[#36]
OP, in your pic of the detent, it looks like you have a brass flake in the RE threads as well.
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Posted: 1/30/2016 10:11:06 AM EST
[#37]
Quote HistoryQuoted: Yes my bolt carrier has a small burr . Going to take care of it this weekend. Thank you for the help . |
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Posted: 1/31/2016 12:59:02 PM EST
[#38]
Quote HistoryQuoted:
You're going to get a new buffer too, right? Quote HistoryQuoted:
Quoted:
Yes my bolt carrier has a small burr . Going to take care of it this weekend. Thank you for the help . My plan was to swap out the buffer when I switched the buffer tube in the next couple of months. Is it a problem to use the buffer currently ? |
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Posted: 2/1/2016 5:27:26 PM EST
[#39]
Quote HistoryQuoted: My plan was to swap out the buffer when I switched the buffer tube in the next couple of months. Is it a problem to use the buffer currently ? Quote HistoryQuoted: Quoted: Quoted: Yes my bolt carrier has a small burr . Going to take care of it this weekend. Thank you for the help . My plan was to swap out the buffer when I switched the buffer tube in the next couple of months. Is it a problem to use the buffer currently ? |
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