User Panel
User Panel
User Panel
|
Posted: 1/28/2018 4:15:35 PM EDT
[#1]
Quote HistoryQuoted:
@mr_stretchy Disagree all you want. There isn't "too many variables" and I already stated my opinion and posted pics of my KAC upper without this damage. The face of the bolt lugs aren't supposed to slam into the extension lugs on their way in and that's the end of it. How could you consider face to face contact between the bolt and barrel extension normal? It may not be that big of an issue for the OP since It's making minimal contact, but trust me, that isn't happening by design.  Quote HistoryQuoted:
Quoted:
Quoted:
Quoted:
Looks like normal wear to me, im no expert by any means but ive been shooting ARs for the last 6 years or so and i personally would not worry about it. the only question i have for you is, does it run? if it does then just shoot it and have fun with it. you should see the lugs on my 7.5". Quoted:
Gross lol. Do you shoot it suppressed? That's what mine look like after a couple hundred rounds suppressed. Disagree all you want. There isn't "too many variables" and I already stated my opinion and posted pics of my KAC upper without this damage. The face of the bolt lugs aren't supposed to slam into the extension lugs on their way in and that's the end of it. How could you consider face to face contact between the bolt and barrel extension normal? It may not be that big of an issue for the OP since It's making minimal contact, but trust me, that isn't happening by design. |
|
|
|
Posted: 1/28/2018 4:23:07 PM EDT
[#2]
Quote HistoryQuoted:
Wrong Quote HistoryQuoted:
Quoted:
Quoted:
Quoted:
Quoted:
Looks like normal wear to me, im no expert by any means but ive been shooting ARs for the last 6 years or so and i personally would not worry about it. the only question i have for you is, does it run? if it does then just shoot it and have fun with it. you should see the lugs on my 7.5". Quoted:
Gross lol. Do you shoot it suppressed? That's what mine look like after a couple hundred rounds suppressed. Disagree all you want. There isn't "too many variables" and I already stated my opinion and posted pics of my KAC upper without this damage. The face of the bolt lugs aren't supposed to slam into the extension lugs on their way in and that's the end of it. How could you consider face to face contact between the bolt and barrel extension normal? It may not be that big of an issue for the OP since It's making minimal contact, but trust me, that isn't happening by design.
See the last few posts above yours for a clear explanation of why it's happening and how to correct it since you don't seem to understand. Even have a pro in here saying its not right and he wouldn't allow it. Wanna know why? Because it's not normal and shouldn't be happening. Not understanding why you think this damage, because that's what it is, is normal and acceptable. |
|
|
|
Posted: 1/28/2018 4:24:34 PM EDT
[#3]
Well damn it, now I am going to go look...
|
|
|
|
Posted: 1/28/2018 4:31:10 PM EDT
[#4]
Quote HistoryQuoted:
Well damn it, now I am going to go look... 
|
|
|
|
Posted: 1/28/2018 4:45:01 PM EDT
[#5]
Quote HistoryQuoted:
Okay, bud. You're right. It's totally normal for the bolt lugs to slam into the barrel extension as the gun cycles. Thanks for clearing it up.
See the last few posts above yours for a clear explanation of why it's happening and how to correct it since you don't seem to understand. Even have a pro in here saying its not right and he wouldn't allow it. Wanna know why? Because it's not normal and shouldn't be happening. Not understanding why you think this damage, because that's what it is, is normal and acceptable. Quote HistoryQuoted:
Quoted:
Quoted:
Quoted:
Quoted:
Quoted:
Looks like normal wear to me, im no expert by any means but ive been shooting ARs for the last 6 years or so and i personally would not worry about it. the only question i have for you is, does it run? if it does then just shoot it and have fun with it. you should see the lugs on my 7.5". Quoted:
Gross lol. Do you shoot it suppressed? That's what mine look like after a couple hundred rounds suppressed. Disagree all you want. There isn't "too many variables" and I already stated my opinion and posted pics of my KAC upper without this damage. The face of the bolt lugs aren't supposed to slam into the extension lugs on their way in and that's the end of it. How could you consider face to face contact between the bolt and barrel extension normal? It may not be that big of an issue for the OP since It's making minimal contact, but trust me, that isn't happening by design.
See the last few posts above yours for a clear explanation of why it's happening and how to correct it since you don't seem to understand. Even have a pro in here saying its not right and he wouldn't allow it. Wanna know why? Because it's not normal and shouldn't be happening. Not understanding why you think this damage, because that's what it is, is normal and acceptable. |
|
|
|
Posted: 1/28/2018 8:16:36 PM EDT
[#6]
Quote HistoryQuoted:
Caused by tolerance stacking. Factors involved include barrel alignment pin notch, gas key/charging handle channel width (where the cam pin rides in the upper) and of course cam pin width. If the barrel truly looks centered (which it is not based on the pics), not likely your alignment pin notch, but don't dismiss this entirely. If the cam pin running area in the upper allows too much play of the cam pin, only real option is replacing the upper if you really don't want these marks. If the cam pin is too narrow on it's own, that's an easy replacement. If it's a stacked factor of all three, then a minor change in any one of them can alleviate this issue. Easiest to do is to find a cam pin with a wider head followed by disassembling the upper and re-torqueing on the barrel. How you do this will dictate the direction the barrel wants to "rest" when done. Use a reaction rod system and the barrel will naturally cant to the right (OPV). Use receiver clamshell and the receiver will naturally cant to the left. If re attaching the barrel clears the issue up but the feed ramps don't appear aligned, no worries. Not a big deal. There's always a chance the feed ramps were machined slightly offset as well, and if the builder used the feed ramps as their alignment "gauge", then the whole thing would be off. Personally, i'd re-torque the barrel to clear this issue up. I wouldn't allow this kind of work out of my shops over seas and I certainly don't allow it when I work on guns for people here at home either. https://imgur.com/a/C8mGG I could see cam pin path and cam pin tolerances causing excess play to make it make contact. I just don’t see how it would produce minimal contact on two lugs and then no contact on others. It would seem to me that if it was hitting some it would hit others. Considering how many rifles this company makes and considering I have had this on 3 of their rifles dating back to 2011 or 12 I would think that I couldn’t possible have the only 3 examples of this. I would have to imagine a lot of people have marks like this on their rifles. I have not read any stories of their rifles breaking bolts left and right. |
|
|
|
Posted: 1/28/2018 8:24:23 PM EDT
[#7]
Quote HistoryQuoted: Okay, bud. You're right. It's totally normal for the bolt lugs to slam into the barrel extension as the gun cycles. Thanks for clearing it up.
See the last few posts above yours for a clear explanation of why it's happening and how to correct it since you don't seem to understand. Even have a pro in here saying its not right and he wouldn't allow it. Wanna know why? Because it's not normal and shouldn't be happening. Not understanding why you think this damage, because that's what it is, is normal and acceptable. “Your upper group received a very thorough inspection and test fire. Based on our analysis, we are confident in stating that your upper and all operating components are functioning well within designed specifications and does not present an area of concern. Please let us know if you have any additional questions,” |
|
|
|
Posted: 1/28/2018 9:02:08 PM EDT
[#8]
Quote HistoryQuoted: The barrel is perfectly centered. https://imgur.com/a/C8mGG I could see cam pin path and cam pin tolerances causing excess play to make it make contact. I just don’t see how it would produce minimal contact on two lugs and then no contact on others. It would seem to me that if it was hitting some it would hit others. Considering how many rifles this company makes and considering I have had this on 3 of their rifles dating back to 2011 or 12 I would think that I couldn’t possible have the only 3 examples of this. I would have to imagine a lot of people have marks like this on their rifles. I have not read any stories of their rifles breaking bolts left and right. You'd just have to measure the dimensions of lugs and all relevant interfaces. |
|
|
|
Posted: 1/28/2018 10:38:04 PM EDT
[#9]
The bolt rides in with it contact when pulling the charging handle back and Riding the bolt into battery very slowly. All bolt lugs are the same width. measured with calipers.
|
|
|
|
Posted: 1/28/2018 11:32:44 PM EDT
[#10]
I looked, I don't have this going on with any.
Okay, some are filthy 
I don't see any contact, though |
|
|
|
Posted: 1/29/2018 2:03:51 AM EDT
[#11]
Quote HistoryQuoted: The barrel is perfectly centered. https://imgur.com/a/C8mGG I could see cam pin path and cam pin tolerances causing excess play to make it make contact. I just don’t see how it would produce minimal contact on two lugs and then no contact on others. It would seem to me that if it was hitting some it would hit others. Considering how many rifles this company makes and considering I have had this on 3 of their rifles dating back to 2011 or 12 I would think that I couldn’t possible have the only 3 examples of this. I would have to imagine a lot of people have marks like this on their rifles. I have not read any stories of their rifles breaking bolts left and right. That being said, there's a canting issue with your BCG/cam pin/receiver. Could possibly even be an out of spec carrier/cam slot. Best thing to do now is swap BCG's and see if a new one does the same thing. Off chance it could be a very strange out of spec part, how's the wear on the bottom of your charge handle where it rests on the carrier key? |
|
|
|
Posted: 1/29/2018 9:47:02 AM EDT
[#12]
Quote HistoryQuoted:
Just an FYI. I had sent in one upper. This was my response. “Your upper group received a very thorough inspection and test fire. Based on our analysis, we are confident in stating that your upper and all operating components are functioning well within designed specifications and does not present an area of concern. Please let us know if you have any additional questions,” Quote HistoryQuoted:
Quoted: Okay, bud. You're right. It's totally normal for the bolt lugs to slam into the barrel extension as the gun cycles. Thanks for clearing it up.
See the last few posts above yours for a clear explanation of why it's happening and how to correct it since you don't seem to understand. Even have a pro in here saying its not right and he wouldn't allow it. Wanna know why? Because it's not normal and shouldn't be happening. Not understanding why you think this damage, because that's what it is, is normal and acceptable. “Your upper group received a very thorough inspection and test fire. Based on our analysis, we are confident in stating that your upper and all operating components are functioning well within designed specifications and does not present an area of concern. Please let us know if you have any additional questions,” |
|
|
|
Posted: 1/29/2018 10:00:28 AM EDT
[#13]
Quote HistoryQuoted:
That's because they didn't wanna fix it. Quote HistoryQuoted:
Quoted:
Quoted: Okay, bud. You're right. It's totally normal for the bolt lugs to slam into the barrel extension as the gun cycles. Thanks for clearing it up.
See the last few posts above yours for a clear explanation of why it's happening and how to correct it since you don't seem to understand. Even have a pro in here saying its not right and he wouldn't allow it. Wanna know why? Because it's not normal and shouldn't be happening. Not understanding why you think this damage, because that's what it is, is normal and acceptable. “Your upper group received a very thorough inspection and test fire. Based on our analysis, we are confident in stating that your upper and all operating components are functioning well within designed specifications and does not present an area of concern. Please let us know if you have any additional questions,” |
|
|
|
Posted: 1/29/2018 10:14:21 AM EDT
[#14]
So, as the channel in the carrier wears, and the cam pin wears, you could see this contact? I have one that is severely overgassed and suppressed, and the cam pin is in need of replacement, it is so worn. I am actually running this one to see the failure point, and it is not allowing this contact
I am not fretting, nor saying the sky will fall, I am actually just curious. |
|
|
|
Posted: 1/29/2018 11:37:48 AM EDT
[#15]
Quote HistoryQuoted: Akshually, the barrel is slight cant right. Extraordinarily minor though and in the wrong direction to be the cause of the issue. ;-) That being said, there's a canting issue with your BCG/cam pin/receiver. Could possibly even be an out of spec carrier/cam slot. Best thing to do now is swap BCG's and see if a new one does the same thing. Off chance it could be a very strange out of spec part, how's the wear on the bottom of your charge handle where it rests on the carrier key? |
|
|
|
Posted: 1/29/2018 11:43:29 AM EDT
[#16]
Quote HistoryQuoted: Akshually, the barrel is slight cant right. Extraordinarily minor though and in the wrong direction to be the cause of the issue. ;-) That being said, there's a canting issue with your BCG/cam pin/receiver. Could possibly even be an out of spec carrier/cam slot. Best thing to do now is swap BCG's and see if a new one does the same thing. Off chance it could be a very strange out of spec part, how's the wear on the bottom of your charge handle where it rests on the carrier key? |
|
|
|
Posted: 1/29/2018 11:50:57 AM EDT
[#17]
Quote HistoryQuoted:
So, as the channel in the carrier wears, and the cam pin wears, you could see this contact? I have one that is severely overgassed and suppressed, and the cam pin is in need of replacement, it is so worn. I am actually running this one to see the failure point, and it is not allowing this contact I am not fretting, nor saying the sky will fall, I am actually just curious. |
|
|
|
Posted: 1/29/2018 11:51:53 AM EDT
[#18]
Quote HistoryQuoted: Hard to swap bcg and see if the wear continues. This wear was there from day one and now on to about 1000 rounds it looks the same. |
|
|
|
Posted: 1/30/2018 12:21:56 AM EDT
[#19]
Quote HistoryQuoted: Hard to swap bcg and see if the wear continues. This wear was there from day one and now on to about 1000 rounds it looks the same. If it's not gotten any worse over time and isn't affecting function, roll with it. |
|
|
|
Posted: 2/1/2018 9:42:37 PM EDT
[#20]
I have one rifle with some wear on a few of the bottom lugs of a bolt. It is a DLC style BCG and the finish is worn off. The metal also seems to show signs of wear in a certain direction, suggestive of the bolt entering the chamber. The rifle has over 2000 rounds and I have not noticed any operational issues. The bolt also functions well when riding it into the chamber, on a test. I get what everyone is saying and it makes sense, that this doesn't seem right. On the other hand I can't say it's abnormal...
|
|
|
|
Posted: 2/4/2018 1:43:34 PM EDT
[#21]
It's just fine....
Shoot it. |
|
|
Win a FREE Membership!
Sign up for the ARFCOM weekly newsletter and be entered to win a free ARFCOM membership. One new winner* is announced every week!
You will receive an email every Friday morning featuring the latest chatter from the hottest topics, breaking news surrounding legislation, as well as exclusive deals only available to ARFCOM email subscribers.
AR15.COM is the world's largest firearm community and is a gathering place for firearm enthusiasts of all types.
From hunters and military members, to competition shooters and general firearm enthusiasts, we welcome anyone who values and respects the way of the firearm.
Subscribe to our monthly Newsletter to receive firearm news, product discounts from your favorite Industry Partners, and more.
Copyright © 1996-2024 AR15.COM LLC. All Rights Reserved.
Any use of this content without express written consent is prohibited.
AR15.Com reserves the right to overwrite or replace any affiliate, commercial, or monetizable links, posted by users, with our own.
