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I need a little help from any RIS II users out there. I recently installed the DD RIS II FSP rail on my 6920 and for some reason the rail is closer to one side of the barrel than the other, the ejection port side specifically. Iraqgunz and I are of the opinion maybe theres something wrong with the rail or the receiver? I have used the provided instructions and tightening pattern and counted my turns to the 1/4 turn and still no dice. So if anyone has had this issue please let me know.
When you installed the barrel nut, is it possible it got scored and the rail isn't sitting flush?
I need a little help from any RIS II users out there. I recently installed the DD RIS II FSP rail on my 6920 and for some reason the rail is closer to one side of the barrel than the other, the ejection port side specifically. Iraqgunz and I are of the opinion maybe theres something wrong with the rail or the receiver? I have used the provided instructions and tightening pattern and counted my turns to the 1/4 turn and still no dice. So if anyone has had this issue please let me know.
As in the barrel nut cross threaded onto the receiver?
The RIS II (it's been a while) uses a small proprietary nut. You have to use that goofy wrench and I wonder if the wrench screwed up a lug (or it slipped) and somehow it scored the barrel nut and now the rail is not setting straight. Maybe something got in the area of the mounting plate?
Maybe you can post some pics and we can see exactly what's happening.
As in the barrel nut cross threaded onto the receiver?
Oh ok I see what you're saying now. I'll take pictures as soon as I can, I'm in the middle of moving and don't have that rifle currently. I had an issue with the first wrench and did that. I got a new wrench and new nut and it went on smooth and this wrench didn't slip off. I'll have to check out the bolt up plate and see what's going on there too.
Send it to IG, he has put many many on, I know cause Ive seen him.
I have installed and removed about a dozen of these over the past month.
If you have installed the barrel nut and rail precisely according to the instructions, and it is still sitting off center, check the surfaces of the components, to ensure that they are finished correctly, without any burrs, or any FOD, especially the front of the receiver, barrel extension, the barrel nut and on the internal surfaces of the rail, especially the "retaining cap" (for want of a better description) that sits between the receiver and the barrel nut. It should rattle around freely, until the six bolts are tightened down, and the rail is pulled against the barrel nut. Also check the threads of both the receiver and inside of the barrel nut for signs of damage or cross threading.
If you have checked all of the above, then look at the surfaces of the parts as you assemble them. Does the barrel appear to sit straight when pushed into the receiver? Does the barrel nut turn freely? does it appear to be properly aligned with the receiver when torqued to 50ft/lb, does the rail go on easily? Does it sit straight when pushed on, and does it stay straight while it is being tightened down? If not, at what point does it start to become misaligned? That should give you some idea of what the cause is, if you have not been able to see anything with your visual inspection.
I hope this helps.
Regards.
Mark
When I reinstalled it with the new barrel nut the bolt up plate does move freely behind the barrel nut and the rail sits flush and straight until all the bolts are snugged down completely. I found that if I backed off 1/4 turn or a little more on the effected side that the rail would be centered in relation to the barrel.
When you loosen up the bolts on the affected side, are you able to tighten the bolts on the opposite side by the same amount, or are they still completely snug?
Regards.
Mark
midSCarolina
05-19-14, 12:51
Not too sure if this will help, but i always tighten the screws about 3/4 of the way, then take an old acog mount (whatever will work as long as it covers a sufficient number of slots) and span the receiver/rail gap to get it straight. Then i go through the whole tightening procedure. Good luck. Pics would be great here if you get a chance.
That is actually really good advice, and something that I forgot to mention.
I use an old A.R.M.S. mount that I had lying around to do the same thing after I had the first one go on a little twisted. I don't know if it helps with keeping the handguard straight, but is certainly appears to help with keeping the handguard top rail lined up with the receiver top rail.
Regards.
Mark
Yeah I just use a carry handle to bridge the gap and hold the rail while i bolt it up. Im just unsure what else to do besides just taking it off and more attentively inspecting each part. Thanks for all the help guys.
Just to be clarify... the carry handle worked?
midSCarolina
05-20-14, 12:42
Yeah I just use a carry handle to bridge the gap and hold the rail while i bolt it up. Im just unsure what else to do besides just taking it off and more attentively inspecting each part. Thanks for all the help guys.
Take it off and try again.... and again, if you can, document it with some pics. Kinda interested. I would personally hate to take the barrel nut off bc i feel like i always f*** it up with that wrench (it would be nice if DD redesigned it with more contact points... its bad when the standard "mil spec" barrel nut is actually easier to deal with than one from a $400 part) Is this the first time you have installed one? I literally put on one last week and got a downward cant at first (i was paying more attention to Jeopardy than the task at hand hah) and had to unbolt and re-bolt and it all went right. Also, if you are looking down the rail, does the rail seem to line up with the rail of the upper receiver?
My 1st try was horrible, I ended up putting the rail and receiver upside down on my counter to make sure it went continually level while I tightened it into place. As long as it all stays touching the counter at all points you should be fine.
Wolfpack45
05-20-14, 15:07
I have installed 9-10 of these and ran into this issue twice. Once was a defective rail and was promptly replaced by Daniel, the other was an out of spec upper receiver where the face of the receiver was not square causing the barrel extension, and thereby the barrel nut and rail to cant to the side like you describe. I would double check the receiver to make sure everything is kosher there. If that is good to go and nothing else seems amiss, perhaps Daniel should have a look at the rail system.
The carry handle works to hold everything true but even after I bolt it all up the rail still pulls toward the ejection port side. I just need to go through and inspect every piece thoroughly. I however currently don't have the rifle and am in the process of moving. Once I get moved and pick up that rifle I'll post pictures. Thanks everyone.
Wow. I've never had that happen before. The RIS, in my experience, has been pretty easy to line up. Might be worthwhile to give DD a heads up on the issue.
Yeah from what everyone has said I'm unsure what the real issue could be. It's either the rail, the receiver, or me. I'll know when I go to IG's armorer's course in June. I'm sure he'll be able to help make the determination as to what the issue is.
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