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Posted: 10/18/2017 12:08:12 AM EDT
THANKS. I RECEIVED A LOT OF GOOD ADVICE AND INFORMATION FROM MEMBERS ABOUT THIS ISSUE (DESCRIBED BELOW). I'M GOING TO CONTACT THE MANUFACTURER. I'LL UPDATE HERE WHEN I LEARN SOMETHING.
I bought a high-end AR from the factory. By high-end, I mean a rifle from a company that is usually mentioned in any list of high-end ARs. The retail price is approaching $2,000. At this point, I would rather not share the name of the company. I have had the rifle for nearly a year, but since I was working overseas, I was not able to shoot it. Yesterday, as I was mounting a red dot on the rail, I noticed that the muzzle looked off-center relative to the rail (that is, the cross-section of the rail while looking directly toward the muzzle). It is not absurdly off-center, but it is noticeable. If you can imagine an X-Y axis superimposed over the face of the rail with the dead center being the origin, then the bore is in Quadrant 3. 
My bore would be at (-1,-1), perhaps even (-2,-2). When I check the rail at the receiver, I don't see any obvious misalignment. There might be a very slight rotation of the rail, and I mean maybe half a degree, but that also could be my imagination or my astigmatism. The screws appear to be tight, but I don't have the correct driver to double check. The apparent offset at the muzzle definitely is real, however. I used the stem of a tire gauge to measure the gap between the rail and the barrel on opposite sides. There seems to be a difference of about 2 ft-lbs of air pressure ;-) by which I mean two tick marks, which is about 2mm. So, the bore is about 2mm lower than the center of the rail and about 2mm to the left of the center of the rail. The rail is full length, stopping just short of the flash suppressor, and that might make the difference more noticeable. Still, I'm not liking it. Does anyone else have a fancy AR that has such a problem (if it is a problem)? Since this a high-priced and supposedly high-quality rifle, am I being reasonable to expect to see the bore directly in the center of the rail? Thanks for any input. |
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Posted: 10/18/2017 12:22:22 AM EDT
[#1]
I'm far from the more knowledgeable crowd here, but I know I've had new handguards look like that and had it be them off center and not the barrel. Maybe try a bore sight on it if you are apprehensive to fire it to see if the barrel is centered and it's just the handguard off center. It's likely an optical illusion and the barrel is fine with the handguard not perfectly aligned.
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Posted: 10/18/2017 12:26:20 AM EDT
[#2]
I had a daniel defense with the same issue. Took the barrel off only to see the indexing pin in the upper receiver was a solid 1/8 inch off center.
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Posted: 10/18/2017 12:31:15 AM EDT
[#3]
Thanks. I also doubt that the barrel itself is out of whack. Still, the hand guard issue bothers me. It seems like either everything is not properly torqued down or the machining is less precise than I would imagine for a rifle this expensive.
Also, after doing a Google search, I see some examples of rails on this rifle rotating significantly during drop tests. That rather disappoints me. |
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Posted: 10/18/2017 12:32:13 AM EDT
[#4]
Quote HistoryQuoted:
I had a daniel defense with the same issue. Took the barrel off only to see the indexing pin in the upper receiver was a solid 1/8 inch off center. |
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Posted: 10/18/2017 12:40:18 AM EDT
[#5]
This ain't that abnormal. Barrels are not 100% centered in the rail. Build enough, you see it.
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Posted: 10/18/2017 12:56:27 AM EDT
[#6]
Quote HistoryQuoted:
This ain't that abnormal. Barrels are not 100% centered in the rail. Build enough, you see it. |
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Posted: 10/18/2017 1:11:10 AM EDT
[#7]
I can only speak for my case and on one rifle but it was the upper receiver slightly off causing the barrel to aim slightly towards the left side of the rifle. I couldn't center it no matter what and my rear sight was was way off to one side. I replaced the upper receiver and now it's perfectly centered.
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Posted: 10/18/2017 1:23:11 AM EDT
[#8]
Quote HistoryQuoted:
Where is the problem most of the time, the barrel or the rail? Quote HistoryQuoted:
Quoted:
This ain't that abnormal. Barrels are not 100% centered in the rail. Build enough, you see it. |
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Posted: 10/18/2017 1:24:24 AM EDT
[#9]
Quote HistoryQuoted:
Interesting. What did you end up doing? |
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Posted: 10/18/2017 1:26:40 AM EDT
[#10]
There are a few factors here. How does the forearm interface with the barrel nut? A common issue is a receiver face that is out of square, so while the barrel is torqued to correct specs, it's out of alignment with the receiver, pitched in other words, so the barrel is cocked a bit in one axis and depending on how the forearm connects to the barrel nut/receiver it is off axis too. Over the last few years I have lapped my receiver face and have observed that my BUIS (front mounted to forearm) require little if any windage adjustments. Before I started lapping, it was not uncommon to have my windage damn near maxed out to one side to zero.
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Posted: 10/18/2017 2:11:19 AM EDT
[#11]
I've owned 3 RIS IIs now and all were off axis to the barrel. A new face plate fixed the issue on the one I did fix. Since then I haven't even bothered since it works fine as is. All 3 cases of mine it was the rail, in how it is mounted/torqued down
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Posted: 10/18/2017 3:05:35 AM EDT
[#12]
Call the company, tell them your concern and see if they have a suggestion. I'm not saying send it back. If they offer a few suggestions, maybe a local gunsmith can square it up.
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Posted: 10/18/2017 4:42:47 AM EDT
[#13]
Quote HistoryQuoted:
Call the company, tell them your concern and see if they have a suggestion. I'm not saying send it back. If they offer a few suggestions, maybe a local gunsmith can square it up. If they tell me it is irrelevant and just an aesthetics thing, I will be disappointed both in the QC and CS. The more I think about the issue, the more I feel things should be close enough to perfect that I cannot see any error simply by looking at it. |
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Posted: 10/18/2017 5:58:01 AM EDT
[#14]
On all my guns my ocd takes over.I would have to have it centered .I always use micrometers to check barrel centering and do whatever it takes to correct on my home builds.
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Posted: 10/18/2017 6:48:43 AM EDT
[#15]
I had to send my DDM4V7 m-lock back because the rail or the mounting was jacked up.
They replaced the entire assembly, but the barrel is still about 1/32" to the right. I like the way the DD guns look and shoot, but I'm not to keen on their way to mount the front rail and handguard. |
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Posted: 10/18/2017 7:25:00 AM EDT
[#16]
Quote HistoryQuoted:
That's kind of where I am on the issue. They have a lifetime guarantee. If they tell me it is irrelevant and just an aesthetics thing, I will be disappointed both in the QC and CS. The more I think about the issue, the more I feel things should be close enough to perfect that I cannot see any error simply by looking at it. Am I wrong? It's obviously bothering you, give them a call. I don't know what company it is, but my guess is that you will be pleasantly surprised by how they handle it. |
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Posted: 10/18/2017 7:39:30 AM EDT
[#17]
I had this problem. Lapped my upper receiver and now its perfect.
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Posted: 10/18/2017 8:19:27 AM EDT
[#18]
Quote HistoryQuoted:
That's kind of where I am on the issue. They have a lifetime guarantee. If they tell me it is irrelevant and just an aesthetics thing, I will be disappointed both in the QC and CS. The more I think about the issue, the more I feel things should be close enough to perfect that I cannot see any error simply by looking at it. Am I wrong? Quote HistoryQuoted:
Quoted:
Call the company, tell them your concern and see if they have a suggestion. I'm not saying send it back. If they offer a few suggestions, maybe a local gunsmith can square it up. If they tell me it is irrelevant and just an aesthetics thing, I will be disappointed both in the QC and CS. The more I think about the issue, the more I feel things should be close enough to perfect that I cannot see any error simply by looking at it. Am I wrong? |
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Posted: 10/18/2017 9:23:56 AM EDT
[#19]
Quote HistoryQuoted:
I had this problem. Lapped my upper receiver and now its perfect. https://www.brownells.com/gunsmith-tools-supplies/rifle-tools/receiver-tools/ar-15-m16-upper-receiver-lapping-tool-prod20220.aspx |
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Posted: 10/18/2017 9:31:34 AM EDT
[#20]
Quote HistoryQuote HistoryQuoted:
Quoted:
I had this problem. Lapped my upper receiver and now its perfect. https://www.brownells.com/gunsmith-tools-supplies/rifle-tools/receiver-tools/ar-15-m16-upper-receiver-lapping-tool-prod20220.aspx |
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Posted: 10/18/2017 9:38:50 AM EDT
[#21]
Depending on the rail you may be able to adjust it to match up with the barrel.
The barrel being a bit high or low in the handguard would be less bothersome to me than being off left or right but I would want it straight as possible. |
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Posted: 10/18/2017 9:44:35 AM EDT
[#22]
The 1st thing you did was contact the manufacture about the issue, right?
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Posted: 10/18/2017 10:06:59 AM EDT
[#23]
Quote HistoryQuoted:
That is definitely something the manufacturer should have done before it left their shop. Quote HistoryQuoted:
Quoted:
Quoted:
I had this problem. Lapped my upper receiver and now its perfect. https://www.brownells.com/gunsmith-tools-supplies/rifle-tools/receiver-tools/ar-15-m16-upper-receiver-lapping-tool-prod20220.aspx However, manufacturers should machine the receiver face perpendicular to the bore, and the outside receiver threads. The outside threads and the receiver face are cut at the same time in the same operation. This is actually the more critical relationship. Some like to lap the receiver face, and what this does is take the receiver face and ensure it is perpendicular to the bore. This actually might take the receiver out of perpendicularity to the receiver threads, which could be bad. That said, we generally aren't talking enough to matter with aluminum threads. |
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Posted: 10/18/2017 10:06:59 AM EDT
[#24]
No pics?
The free float hand guard sounds like it's doing its job. |
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Posted: 10/18/2017 10:19:00 AM EDT
[#25]
How about you shoot it to see if there's a real issue?
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Posted: 10/18/2017 10:25:26 AM EDT
[#26]
Quote HistoryQuoted:
Manufacturers should not lap receiver faces. However, manufacturers should machine the receiver face perpendicular to the bore, and the outside receiver threads. The outside threads and the receiver face are cut at the same time in the same operation. This is actually the more critical relationship. Some like to lap the receiver face, and what this does is take the receiver face and ensure it is perpendicular to the bore. This actually might take the receiver out of perpendicularity to the receiver threads, which could be bad. That said, we generally aren't talking enough to matter with aluminum threads. Quote HistoryQuoted:
Quoted:
Quoted:
Quoted:
I had this problem. Lapped my upper receiver and now its perfect. https://www.brownells.com/gunsmith-tools-supplies/rifle-tools/receiver-tools/ar-15-m16-upper-receiver-lapping-tool-prod20220.aspx However, manufacturers should machine the receiver face perpendicular to the bore, and the outside receiver threads. The outside threads and the receiver face are cut at the same time in the same operation. This is actually the more critical relationship. Some like to lap the receiver face, and what this does is take the receiver face and ensure it is perpendicular to the bore. This actually might take the receiver out of perpendicularity to the receiver threads, which could be bad. That said, we generally aren't talking enough to matter with aluminum threads. The OP paid for and should have received a “high quality” rifle. Obviously he didn’t. To add, with something so easy to see, it makes me wonder what you can’t or don’t see. “How you do one thing is how you do everything.” |
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Posted: 10/18/2017 10:43:12 AM EDT
[#27]
My good friends rifle had this issue with the gas block not fitting under the hand guards and it applied pressure to the hand guard.
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Posted: 10/18/2017 10:49:12 AM EDT
[#28]
Daniel Defense rifles have this problem a lot. It can actually be resolved by varying the tightness of the 4 or 6 clamping screws at the receiver end of the barrel. They tend to “pull” the rail one way or the other, so you can tighten or loosen them very slightly (I’m talking 1/8 or 1/16 turns) in order to center the rail around the barrel.
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Posted: 10/18/2017 2:23:47 PM EDT
[#29]
Quote HistoryQuoted:
Daniel Defense rifles have this problem a lot. It can actually be resolved by varying the tightness of the 4 or 6 clamping screws at the receiver end of the barrel. They tend to “pull” the rail one way or the other, so you can tighten or loosen them very slightly (I’m talking 1/8 or 1/16 turns) in order to center the rail around the barrel. |
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Posted: 10/18/2017 3:20:19 PM EDT
[#30]
You'll get this problem with all rails, especially rails designed to sit flush against the front face of the upper.
It is annoying having to dial windage to get your rifle zeroed if you rail mount a front sight. |
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Posted: 10/18/2017 3:58:36 PM EDT
[#31]
I like to use 15" rails, so I lap the front face of the receiver to get the barrel centered in the rail. It does make a difference, otherwise the barrel axis will be off-centered inside the rail.
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Posted: 10/18/2017 4:15:19 PM EDT
[#32]
So the bore is 2mm left and 2mm down relative to the rail at the very end/muzzle area?
That doesn't seems like alot to me... Maybe provide a picture? |
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Posted: 10/18/2017 4:21:15 PM EDT
[#33]
Quote HistoryQuoted:
Call the company, tell them your concern and see if they have a suggestion. I'm not saying send it back. If they offer a few suggestions, maybe a local gunsmith can square it up. 
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Posted: 10/18/2017 4:26:35 PM EDT
[#34]
Quote HistoryQuoted:
“How you do one thing is how you do everything.” |
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Posted: 10/18/2017 4:38:16 PM EDT
[#35]
Is accuracy less than what you expected? Is function affected at all?
Even if it's just aesthetic, call the manufacturer and see what they offer to do. If they don't offer to do anything, and function isn't affected at all, I would leave it alone. You might break something trying to fix what doesn't need fixing. |
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Posted: 10/18/2017 4:52:05 PM EDT
[#36]
As long as it'll zero out with some usable amount of adjustability in every direction after zeroing, don't sweat it.
If you take your riflescope and place the objective end on a mirror and sight through it, (illuminated reticle turned on if you have one) and adjust it so that the two visible crosshairs line up exactly, then at this point your scope should be perfectly collimated. (All optics in a perfect lineup) Set the windages to zero at this setting. Now mount the scope on your rifle and zero to point of aim at your chosen zeroing range. I did this. And I was not really very thrilled at just how far off it was, laterally, as compared to its collimated setting. This is a Leupold scope in either ARMS #22H rings OR a LaRue LT-something mount on a rifle built with all top quality components. I tried both mount systems and between the two of them the shift in point of aim was actually negligible. So my presumption there is that both sets of rings are made right. Can't fault either company. In a perfect world, I would not have had to TOUCH the windage and only had to make vertical adjustments to move point of aim to point of impact. While this does bother me ever so slightly, I realize that really this is par for the course. I did some checking and the amount of adjustment I had to make was well within the normal range, so sayeth Leupold. So don't worry about a variation between the "natural" point of aim of the optic and the point of impact. As long as you can align them without running out of travel, that's functionally good enough. If it really bothers you, there are things you can do to isolate the problem. For example, I could re-collimate my scope and then rotate it in the rings and see if its point of aim shifts around. In the collimated setting there should be no shift in point of aim at all as you rotate the scope. |
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Posted: 10/18/2017 5:04:47 PM EDT
[#37]
Quote HistoryQuoted:
Would this fix the problem permanently then? Could you be assured that your backup front sight would remain stable? Quote HistoryQuoted:
Quoted:
Daniel Defense rifles have this problem a lot. It can actually be resolved by varying the tightness of the 4 or 6 clamping screws at the receiver end of the barrel. They tend to “pull” the rail one way or the other, so you can tighten or loosen them very slightly (I’m talking 1/8 or 1/16 turns) in order to center the rail around the barrel. If you had a freshly installed DD rail and the rifle was left leaning against something for a year it may have actually shifted. Because of the clamp style lock up they can settle into a different position but it usually happens after just a day or so. Adjusting the bolts fixes it and it will stay that way solid and forever. The rail position has no effect on the fronts sight stability, only the POI between the sights may need adjusted if the rail (front sight) is shifted. |
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Posted: 10/18/2017 7:41:02 PM EDT
[#38]
Beat the hand guard until it breaks or gets straight. Or, simply inform the manufacturer who will replace the upper half.
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Posted: 10/18/2017 8:13:16 PM EDT
[#39]
Do you have a set of sights on it, or just an optic mounted to the receiver? If no sights, how would it actually affect accuracy?
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Posted: 10/18/2017 8:19:31 PM EDT
[#40]
I'm going to guess KAC SR-15e3 mod 1.
Reason I assume this is because it's a very common assembly error that causes this. The assembler is supposed to screw the rail (URX3.1) on until it hits the receiver, then back it off to align it. It is all too tempting to screw it on further to align it, and that's what causes this. I had the same issue, feel free to PM me if this is indeed the rifle you have and want a fix. Quoted:
I bought a high-end AR from the factory. By high-end, I mean a rifle from a company that is usually mentioned in any list of high-end ARs. The retail price is approaching $2,000. At this point, I would rather not share the name of the company. I have had the rifle for nearly a year, but since I was working overseas, I was not able to shoot it. Yesterday, as I was mounting a red dot on the rail, I noticed that the muzzle looked off-center relative to the rail (that is, the cross-section of the rail while looking directly toward the muzzle). It is not absurdly off-center, but it is noticeable. If you can imagine an X-Y axis superimposed over the face of the rail with the dead center being the origin, then the bore is in Quadrant 3. http://www.math.com/school/subject2/images/S2U4L1DP.gif My bore would be at (-1,-1), perhaps even (-2,-2). When I check the rail at the receiver, I don't see any obvious misalignment. There might be a very slight rotation of the rail, and I mean maybe half a degree, but that also could be my imagination or my astigmatism. The screws appear to be tight, but I don't have the correct driver to double check. The apparent offset at the muzzle definitely is real, however. I used the stem of a tire gauge to measure the gap between the rail and the barrel on opposite sides. There seems to be a difference of about 2 ft-lbs of air pressure ;-) by which I mean two tick marks, which is about 2mm. So, the bore is about 2mm lower than the center of the rail and about 2mm to the left of the center of the rail. The rail is full length, stopping just short of the flash suppressor, and that might make the difference more noticeable. Still, I'm not liking it. Does anyone else have a fancy AR that has such a problem (if it is a problem)? Since this a high-priced and supposedly high-quality rifle, am I being reasonable to expect to see the bore directly in the center of the rail? Thanks for any input. |
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Posted: 10/18/2017 11:36:14 PM EDT
[#41]
Quote HistoryQuoted:
On all my guns my ocd takes over.I would have to have it centered .I always use micrometers to check barrel centering and do whatever it takes to correct on my home builds. |
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Posted: 10/18/2017 11:36:57 PM EDT
[#42]
Quote HistoryQuoted:
I'm going to guess KAC SR-15e3 mod 1. Reason I assume this is because it's a very common assembly error that causes this. The assembler is supposed to screw the rail (URX3.1) on until it hits the receiver, then back it off to align it. It is all too tempting to screw it on further to align it, and that's what causes this. I had the same issue, feel free to PM me if this is indeed the rifle you have and want a fix. It was kind of bad, which the rear sight needed to adjust 23 clicks to the left to compensate. (34 clicks to max out on either side) I had a thread about this in the KAC sub section, and did a RMA. KAC later fixed the problem on the upper, and I've been very happy with it since. |
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Posted: 10/19/2017 12:05:31 AM EDT
[#43]
Quote HistoryQuoted:
Ummmm, no. Places that need to make money running parts spend time where time counts to the finished product. Quote HistoryQuoted:
Quoted:
“How you do one thing is how you do everything.” |
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Posted: 10/19/2017 5:10:59 AM EDT
[#44]
Think about this for a minute.
You have two parts, 15 and 16 inches in length. Attached at one spot near each other. One is a hollow aluminum tube. It will flex. Even if it were perfect, laser aligned, if you actually use the thing it will end up being off eventually. |
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Posted: 10/19/2017 7:52:42 PM EDT
[#45]
Quote HistoryQuoted:...To add, with something so easy to see, it makes me wonder what you can’t or don’t see. |
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Posted: 10/19/2017 7:56:47 PM EDT
[#46]
Quote HistoryQuoted:
So the bore is 2mm left and 2mm down relative to the rail at the very end/muzzle area? That doesn't seems like alot to me... Maybe provide a picture? |
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Posted: 10/19/2017 8:38:31 PM EDT
[#47]
Quote HistoryQuoted:
That's correct. It's not a lot, but I can see the difference easily enough. I haven't had luck taking pictures, not because they don't show the barrel out of center, but because the pictures greatly exaggerate the problem. I guess I should try a real camera resting on a table rather than a phone. Quote HistoryQuoted:
Quoted:
So the bore is 2mm left and 2mm down relative to the rail at the very end/muzzle area? That doesn't seems like alot to me... Maybe provide a picture? I have had great success with Wheeler's receiver lapping tool kit in fixing this on two different uppers. About $25 or less, most vendors. |
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Posted: 10/19/2017 11:55:33 PM EDT
[#48]
Quote HistoryQuoted:
That's correct. It's not a lot, but I can see the difference easily enough. I haven't had luck taking pictures, not because they don't show the barrel out of center, but because the pictures greatly exaggerate the problem. I guess I should try a real camera resting on a table rather than a phone. Since I don't have the old pictures anymore, I took a look at the corrected upper(which KAC fixed), and I remember it might be about 3mm off to the left, and 2mm down, at quatrant 3 just like your rifle... I remember the top of the gas block was almost touching the top narrow channel of the URX3.1 rail. And again, as I mentioned, that rifle needed its rear sight to adjust 23 clicks to the left to compensate. (34 clicks to max out on either side) I'd say you should shoot it with iron sight, and see if it needed to be returned to the manufacturer, whoever it might be. From my personal experience, it probably needed to be fixed... |
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Posted: 10/21/2017 4:31:28 PM EDT
[#49]
Quote HistoryQuoted:
I'd say you should shoot it with iron sight, and see if it needed to be returned to the manufacturer, whoever it might be. From my personal experience, it probably needed to be fixed... |
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Posted: 10/22/2017 11:25:46 PM EDT
[#50]
Quote HistoryQuoted:
Think about this for a minute. You have two parts, 15 and 16 inches in length. Attached at one spot near each other. One is a hollow aluminum tube. It will flex. Even if it were perfect, laser aligned, if you actually use the thing it will end up being off eventually. |
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