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Posted: 3/29/2015 3:38:38 PM EDT
Just noticed this wear when cleaning this morning. Any ideas what's causing this? I'm aware the groove next to the cam pin is normal, but what about the channels going back 3/4 up the upper receiver? They didn't appear until i started shooting it with the short barrel and the can. It previously had a 16" barrel and no can. Probably several thousand through the upper, but in this configuration only about 500.
The channels are above the carrier itself. They are exactly the same height as the top of the cam pin and gas key. There are literally channels cut into the aluminum, not just finish wear. You can see pieces of the metal flaking off in the pictures. They aren't deep yet, but I don't want to keep shooting this thing if this isn't normal. The upper is a VLTOR VIS 2A. Could excessive gas cause this type of wear? Maybe I'm just needing an adjustable gas block and heavier buffer ? Here's the specs. 11.5" barrel. Specwar 556. Carbine buffer. m16 carrier. I've never seen the cam pin cause channels like this before, esp on both sides. 
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Posted: 3/29/2015 4:00:51 PM EDT
[#1]
Looks like charging handle wear. If so, normal.
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Posted: 3/29/2015 4:13:42 PM EDT
[#2]
Definitely not charging handle wear
Quote HistoryQuoted:
Looks like charging handle wear. If so, normal. |
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Posted: 3/29/2015 5:05:29 PM EDT
[#3]
Check your cam pin for ware looks like it was rubbing looks to high for the retaining pin to have done it
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Posted: 3/29/2015 5:07:48 PM EDT
[#4]
Looks fine to me. Lubricate all friction areas generously and it shouldn't become a problem. Whatever is causing it already made its path, meaning it won't get worse, esp with lubrication
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Posted: 3/29/2015 5:12:20 PM EDT
[#5]
Quote HistoryQuoted:
Looks fine to me. Lubricate all friction areas generously and it shouldn't become a problem. Whatever is causing it already made its path, meaning it won't get worse, esp with lubrication Yeah you just broke it in basically |
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Posted: 3/29/2015 5:15:14 PM EDT
[#6]
What wear?
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Posted: 3/29/2015 6:15:52 PM EDT
[#7]
Quote HistoryQuoted:
What wear? That's what I'm thinking... |
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Posted: 3/29/2015 7:07:13 PM EDT
[#8]
Quote HistoryQuoted:
Looks fine to me. Lubricate all friction areas generously and it shouldn't become a problem. Whatever is causing it already made its path, meaning it won't get worse, esp with lubrication This is what I was hoping to hear. I just wanted to confirm before making a potential problem worse. Thanks |
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Posted: 3/29/2015 8:26:56 PM EDT
[#9]
Quote HistoryQuoted:
Definitely not charging handle wear No offense, but I love how people ask "what is this?" Then proceed to DISAGREE with the answers they get. |
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Posted: 3/29/2015 8:41:35 PM EDT
[#10]
That is not "normal" wear!
Finish wear is one thing but the pieces of aluminum that were scraped off are still in the receiver. None of the AR's I have bought or built have ever shown wear like that, especially with that low of a round count. |
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Posted: 3/29/2015 8:50:34 PM EDT
[#11]
How about some pictures of the bolt carrier group, it should show some scratches of what exactly is cutting those channels.
It doesn't look right to me. |
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Posted: 3/29/2015 8:58:25 PM EDT
[#12]
Quote HistoryQuoted:
No offense, but I love how people ask "what is this?" Then proceed to DISAGREE with the answers they get. Quote HistoryQuoted:
Quoted:
Definitely not charging handle wear No offense, but I love how people ask "what is this?" Then proceed to DISAGREE with the answers they get. In this case the OP is right is disagreeing. The wear is on the receiver sides below the charging handle track. |
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Posted: 3/29/2015 9:09:17 PM EDT
[#13]
Quote HistoryQuoted:
In this case the OP is right is disagreeing. The wear is on the receiver sides below the charging handle track. Quote HistoryQuoted:
Quoted:
Quoted:
Definitely not charging handle wear No offense, but I love how people ask "what is this?" Then proceed to DISAGREE with the answers they get. In this case the OP is right is disagreeing. The wear is on the receiver sides below the charging handle track. You're right. I see it now. My apologies OP. |
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Posted: 3/29/2015 9:18:02 PM EDT
[#14]
Quote HistoryQuoted:
You're right. I see it now. My apologies OP. Quote HistoryQuoted:
Quoted:
Quoted:
Quoted:
Definitely not charging handle wear No offense, but I love how people ask "what is this?" Then proceed to DISAGREE with the answers they get. In this case the OP is right is disagreeing. The wear is on the receiver sides below the charging handle track. You're right. I see it now. My apologies OP. Its all good! 
I was wrong once too..........well according to my wife that is! |
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Posted: 3/29/2015 9:52:36 PM EDT
[#15]
Fat gas key?
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Posted: 3/29/2015 10:04:44 PM EDT
[#16]
Quote HistoryQuoted:
How about some pictures of the bolt carrier group, it should show some scratches of what exactly is cutting those channels. It doesn't look right to me. This! |
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Posted: 3/29/2015 10:24:24 PM EDT
[#17]
Quote HistoryQuoted:
Check your cam pin for wear looks like it was rubbing looks to high for the retaining pin to have done it ^^ this^^ |
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Posted: 3/30/2015 1:21:57 AM EDT
[#18]
I didn't see anything out of the ordinary when i looked, but i'll get some pics up tomorrow in case I missed something.
What about being over gassed ? Is that a possibility? Quote HistoryQuoted:
^^ this^^ Quote HistoryQuoted:
Quoted:
Check your cam pin for wear looks like it was rubbing looks to high for the retaining pin to have done it ^^ this^^ |
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Posted: 3/30/2015 1:24:44 AM EDT
[#19]
Quote HistoryQuoted: What wear? |
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Posted: 3/30/2015 8:12:42 AM EDT
[#20]
Quote HistoryQuoted: Quote HistoryQuoted: Quoted: What wear? |
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Posted: 3/30/2015 8:37:30 AM EDT
[#21]
Quote HistoryQuoted:
Quote HistoryQuoted:
Quoted:
What wear? 
The cam pin head is dragging horribly on the closing stroke, and it starts around the time the bolt starts to encounter resistance from picking up a round from the magazine (note where it fades out). That damage looks to be about 0.03" to 0.04" deep you may have to scrap that upper. |
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Posted: 3/30/2015 9:27:32 AM EDT
[#22]
This explanation makes sense to me. Any idea what would cause that? Why do you say the upper is no good now ?
Quote HistoryQuoted:
http://i1242.photobucket.com/albums/gg538/lysanderx/20150329_090449_zps2qfxmpwi.jpg The cam pin head is dragging horribly on the closing stroke, and it starts around the time the bolt starts to encounter resistance from picking up a round from the magazine (note where it fades out). That damage looks to be about 0.03" to 0.04" deep you may have to scrap that upper. Quote HistoryQuoted:
Quoted:
Quoted:
What wear? http://i1242.photobucket.com/albums/gg538/lysanderx/20150329_090449_zps2qfxmpwi.jpg The cam pin head is dragging horribly on the closing stroke, and it starts around the time the bolt starts to encounter resistance from picking up a round from the magazine (note where it fades out). That damage looks to be about 0.03" to 0.04" deep you may have to scrap that upper. |
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Posted: 3/30/2015 10:20:19 AM EDT
[#23]
Quote HistoryQuoted:
This explanation makes sense to me. Any idea what would cause that? Why do you say the upper is no good now ? Lack of lubrication? Can't really say without more information. A picture of the cam pin would help. And, maybe a few of the bolt carrier and all its associated parts. Well, I don't think it would pass the inspections in the TM. |
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Posted: 3/30/2015 10:36:47 AM EDT
[#24]
Quote HistoryLack of lubrication?
Can't really say without more information. A picture of the cam pin would help. And, maybe a few of the bolt carrier and all its associated parts. Well, I don't think it would pass the inspections in the TM. I should be able to snap some pics later today. Now that I think about it, the only part on this rifle I haven't used before was the BCG. It was a warranty replacement from SA&A. The first bolt was...out of spec. So bad that certain magazines wouldn't insert. If the BCG is the problem, I wonder if I have any recourse. This upper is monolithic so I'm out a lot of money if it's toast. What is TM ? Would any measurements of certain parts help ? |
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Posted: 3/30/2015 12:43:27 PM EDT
[#25]
Here's pics of the BCG. I measured the cam pin and compared it to some of my others. It measured .400 wide like my others, but It measures .321 long, while all of my others measured .317. Not sure if that could cause it?
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Posted: 3/30/2015 12:48:54 PM EDT
[#26]
Measure the cam on the other sides, the dimension shown doesn't matter, the width does.
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Posted: 3/30/2015 1:03:29 PM EDT
[#27]
I mentioned it in my post. It's .400 wide.
Quote HistoryQuoted:
Measure the cam on the other sides, the dimension shown doesn't matter, the width does. |
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Posted: 3/30/2015 1:46:10 PM EDT
[#28]
Mine has worse wear than that and runs like a raped ape.
I wouldn't worry about it It is definitely wear from a cam pin |
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Posted: 3/30/2015 3:56:09 PM EDT
[#29]
Quote HistoryQuoted:
http://i1242.photobucket.com/albums/gg538/lysanderx/20150329_090449_zps2qfxmpwi.jpg The cam pin head is dragging horribly on the closing stroke, and it starts around the time the bolt starts to encounter resistance from picking up a round from the magazine (note where it fades out). That damage looks to be about 0.03" to 0.04" deep you may have to scrap that upper. Quote HistoryQuoted:
Quoted:
Quoted:
What wear? http://i1242.photobucket.com/albums/gg538/lysanderx/20150329_090449_zps2qfxmpwi.jpg The cam pin head is dragging horribly on the closing stroke, and it starts around the time the bolt starts to encounter resistance from picking up a round from the magazine (note where it fades out). That damage looks to be about 0.03" to 0.04" deep you may have to scrap that upper. You really think a scratch is going to compromise the strength of a receiver? |
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Posted: 3/30/2015 4:10:51 PM EDT
[#30]
No reason to scrap it OP. Is your wear pattern common? No.
Is it going to get worse? No. The wear path is already made. Is it going to cause a malfunction? No. The wear path is already made. Lubricate the shit out of it and don't worry about it. I whole heartedly don't see it as an issue in your case. The cam pin already made its path. |
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Posted: 3/30/2015 5:38:30 PM EDT
[#31]
Quote HistoryQuoted:
This explanation makes sense to me. Any idea what would cause that? Why do you say the upper is no good now ? Quote HistoryQuoted:
This explanation makes sense to me. Any idea what would cause that? Why do you say the upper is no good now ? Quoted:
Quoted:
Quoted:
What wear? http://i1242.photobucket.com/albums/gg538/lysanderx/20150329_090449_zps2qfxmpwi.jpg The cam pin head is dragging horribly on the closing stroke, and it starts around the time the bolt starts to encounter resistance from picking up a round from the magazine (note where it fades out). That damage looks to be about 0.03" to 0.04" deep you may have to scrap that upper. How do your bolt gas rings look. Wes |
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Posted: 3/30/2015 6:59:19 PM EDT
[#32]
It is not going to weaken the upper, but it ate through the anodizing.
Check the areas circled for burrs, raised edges or really sharp corners. I would also check the cam pin to see if the hole for the firing pin is at 90 degrees to the flats. To check this take the pin out and clamp in the dial indicator, just like you're measuring in the photo, then slip the firing pin in the hole and see if it is parallel to the arm. To prevent the groove getting worse knock of any burrs, etc found and keep it well lubricated. And, I would coat the inside of the upper with dryfilm lube, if you have some. 
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Posted: 3/30/2015 8:38:49 PM EDT
[#33]
From the pics you posted of your bcg, it looks like the most wear is on the corners of your gas-key. That is my guess. The cam pin, even if it were wider than the gas-key, isn't thick enough to make tracks that wide. The gas-key on the other hand...
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Posted: 3/30/2015 8:46:03 PM EDT
[#34]
If the BCG is steel, I dont think he'll see any wear on that. All the wear would just be on the upper. Maybe a burr from sloppy manufacturing but from the pics of the receiver, burrs that could cause something like that would be pretty obvious, at least until the aluminum manages to knock off that extra steel
And the extra length on the cam pin could be the cause. Tolerance stacking between the reciever and BCG and whatnot. |
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Posted: 3/30/2015 11:11:44 PM EDT
[#35]
Quote HistoryQuoted:
Mine has worse wear than that and runs like a raped ape. I wouldn't worry about it It is definitely wear from a cam pin Yup... I wouldn't say worse but similar. There are a few thousand rounds thru mine tho  . I'll post a pic tomorrow
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Posted: 3/31/2015 3:29:05 AM EDT
[#36]
Quoted:
Just noticed this wear when cleaning this morning. Any ideas what's causing this? I'm aware the groove next to the cam pin is normal, but what about the channels going back 3/4 up the upper receiver? They didn't appear until i started shooting it with the short barrel and the can. It previously had a 16" barrel and no can. Probably several thousand through the upper, but in this configuration only about 500. The channels are above the carrier itself. They are exactly the same height as the top of the cam pin and gas key. There are literally channels cut into the aluminum, not just finish wear. You can see pieces of the metal flaking off in the pictures. They aren't deep yet, but I don't want to keep shooting this thing if this isn't normal. The upper is a VLTOR VIS 2A. Could excessive gas cause this type of wear? Maybe I'm just needing an adjustable gas block and heavier buffer ? Here's the specs. 11.5" barrel. Specwar 556. Carbine buffer. m16 carrier. I've never seen the cam pin cause channels like this before, esp on both sides. http://i859.photobucket.com/albums/ab151/blc628/upper%20wear/20150329_090449_zpsbfd4rdor.jpg http://i859.photobucket.com/albums/ab151/blc628/upper%20wear/20150329_090820_zpsprly7e3t.jpg http://i859.photobucket.com/albums/ab151/blc628/upper%20wear/20150329_090704_zpsrhffeggx.jpg http://i859.photobucket.com/albums/ab151/blc628/upper%20wear/20150329_090646_zpsqbfjluza.jpg You migh have pinched the receiver during the barrel swap, narrowing the BCG raceway and cam pin channel at the weakest point in the upper, behind the ejection port. This usually happens from over tightening the vice when using a set of blocks or a clam shell to hold the upper. If you take a 1" piece of AL bar stock and slide it into the upper after the BCG is removed, you can locate the area where it is pinched when you feel resistance. |
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Posted: 3/31/2015 8:21:41 AM EDT
[#37]
Quote HistoryQuoted:
How do your bolt gas rings look. Wes Quote HistoryQuoted:
Quoted:
This explanation makes sense to me. Any idea what would cause that? Why do you say the upper is no good now ? Quoted:
Quoted:
Quoted:
What wear? http://i1242.photobucket.com/albums/gg538/lysanderx/20150329_090449_zps2qfxmpwi.jpg The cam pin head is dragging horribly on the closing stroke, and it starts around the time the bolt starts to encounter resistance from picking up a round from the magazine (note where it fades out). That damage looks to be about 0.03" to 0.04" deep you may have to scrap that upper. How do your bolt gas rings look. Wes OP...what do your gas rings look like? Will they hold the bolt carrier up if you extend the bolt and the stand the assembly on the bolt face or dose the carrier's weight force the assembly into the compressed position? Are any of your gas rings larger than the others? Are the gas rings tangled or bent in any way? Wes |
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Posted: 3/31/2015 11:01:04 AM EDT
[#38]
Quote HistoryQuoted:
Yup... I wouldn't say worse but similar. There are a few thousand rounds thru mine tho (ETA... looks like you are a few k in too... i personally think your wear is fairly normal). I'll post a pic tomorrow
Quote HistoryQuoted:
Quoted:
Mine has worse wear than that and runs like a raped ape. I wouldn't worry about it It is definitely wear from a cam pin Yup... I wouldn't say worse but similar. There are a few thousand rounds thru mine tho (ETA... looks like you are a few k in too... i personally think your wear is fairly normal). I'll post a pic tomorrow
As promised... wear inside my BCM 11.5 
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Posted: 3/31/2015 5:19:13 PM EDT
[#39]
Thanks for the pics Thornejc. Nice to know I'm not the only one.
I took it out shooting again the other day and dialed the gas waaay down, to the point it only cycles with the can on it now, and put in an H3 buffer. The damage does not seem to be any worse, so hopefully you guys are right and it'll be just fine. Worst case, it will make a nice 22lr upper i suppose. Quote HistoryOP...what do your gas rings look like? Will they hold the bolt carrier up if you extend the bolt and the stand the assembly on the bolt face or dose the carrier's weight force the assembly into the compressed position? Are any of your gas rings larger than the others? Are the gas rings tangled or bent in any way? Wes They look good. The bolt will not collapse under it's own weight. |
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Posted: 4/1/2015 6:08:01 PM EDT
[#40]
Quote HistoryQuoted:
Thanks for the pics Thornejc. Nice to know I'm not the only one. I took it out shooting again the other day and dialed the gas waaay down, to the point it only cycles with the can on it now, and put in an H3 buffer. The damage does not seem to be any worse, so hopefully you guys are right and it'll be just fine. Worst case, it will make a nice 22lr upper i suppose. They look good. The bolt will not collapse under it's own weight. Quote HistoryQuoted:
Thanks for the pics Thornejc. Nice to know I'm not the only one. I took it out shooting again the other day and dialed the gas waaay down, to the point it only cycles with the can on it now, and put in an H3 buffer. The damage does not seem to be any worse, so hopefully you guys are right and it'll be just fine. Worst case, it will make a nice 22lr upper i suppose. OP...what do your gas rings look like? Will they hold the bolt carrier up if you extend the bolt and the stand the assembly on the bolt face or dose the carrier's weight force the assembly into the compressed position? Are any of your gas rings larger than the others? Are the gas rings tangled or bent in any way? Wes They look good. The bolt will not collapse under it's own weight. Checked LMT 10.5 and same type of wear. That rifle is prob pushing 10k rounds |
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