View Full Version : DDM4/SLiM rail anti-rotation problem?
justin_247
11-06-16, 10:52
I was just watching this video review of a DD rifle with the SLiM rail from AK Operators Union on YouTube, and at 1:25 you can see where the rail rotated slightly, maxing out the anti-rotation tabs.
https://youtu.be/QQOa5B_66oY?t=1m25s
This is one of the things I was wondering about after I installed my DDM4 rail, since the anti-rotation tabs aren't actually "fit" to the receiver and allow some play if sufficient force was applied. This is a problem if you are shooting with BUIS (which I do, occasionally). Additionally, the barrel nut is smooth with no knurling, with the rail is attached to the nut simply by a plate behind the nut that screwed into the rail... without anything providing additional friction to prevent it from rotating. Without knurling, I can definitely see how the rail could rotate on the nut.
In addition to the problems this would generate for your BUIS' zero, the tight tolerances inside the rail could also cause the rail to no longer be truly free floated, since the rail may contact the gas block. I have a BCM lo-pro gas block under my rail, and it wouldn't take much rotation for the rail to touch it.
And, if you make the ill-advised decision to bridge the gap between the receiver and the rail with your scope mount, this could cause the scope to be thrown off zero, as well.
BCM's anti-rotation solution seems superior here, in that the tabs are actually more "fitted" to the upper receiver. But I don't know how tough they are, so don't take my word for this.
Honestly, I don't think this would affect function and I'm not going to swap out my rail anytime soon, but, in retrospect, I probably should have purchased a rail that allowed me to keep my front sight post. This post is NOT a dig at DD, and I will continue to purchase DD products in the future with confidence. BUT, if you shoot with BUIS from time to time, I definitely encourage you to keep your FSP.
This post is NOT a dig at DD. If you want to attack DD, go elsewhere.
Mrgunsngear
11-06-16, 11:12
I was just watching this video review of a DD rifle with the SLiM rail from AK Operators Union on YouTube, and at 1:25 you can see where the rail rotated slightly, maxing out the anti-rotation tabs.
https://youtu.be/QQOa5B_66oY?t=1m25s
This is one of the things I was wondering about after I installed my DDM4 rail, since the anti-rotation tabs aren't actually "fit" to the receiver and allow some play if sufficient force was applied. This is a problem if you are shooting with BUIS (which I do, occasionally). Additionally, the barrel nut is smooth with no knurling, with the rail is attached to the nut simply by a plate behind the nut that screwed into the rail... without anything providing additional friction to prevent it from rotating. Without knurling, I can definitely see how the rail could rotate on the nut.
In addition to the problems this would generate for your BUIS' zero, the tight tolerances inside the rail could also cause the rail to no longer be truly free floated, since the rail may contact the gas block. I have a BCM lo-pro gas block under my rail, and it wouldn't take much rotation for the rail to touch it.
And, if you make the ill-advised decision to bridge the gap between the receiver and the rail with your scope mount, this could cause the scope to be thrown off zero, as well.
BCM's anti-rotation solution seems superior here, in that the tabs are actually more "fitted" to the upper receiver. But I don't know how tough they are, so don't take my word for this.
Honestly, I don't think this would affect function and I'm not going to swap out my rail anytime soon, but, in retrospect, I probably should have purchased a rail that allowed me to keep my front sight post. This post is NOT a dig at DD, and I will continue to purchase DD products in the future with confidence. BUT, if you shoot with BUIS from time to time, I definitely encourage you to keep your FSP.
This post is NOT a dig at DD. If you want to attack DD, go elsewhere.
Embed:
http://youtu.be/QQOa5B_66oY?t=1m25s
10,000 rounds through my V5 and it's has not shifted at all.
Wolfpack45
11-07-16, 10:14
Any properly installed, properly torqued rail system should not shift without serious abuse.
I was just watching this video review of a DD rifle with the SLiM rail from AK Operators Union on YouTube, and at 1:25 you can see where the rail rotated slightly, maxing out the anti-rotation tabs.
https://youtu.be/QQOa5B_66oY?t=1m25s
This is one of the things I was wondering about after I installed my DDM4 rail, since the anti-rotation tabs aren't actually "fit" to the receiver and allow some play if sufficient force was applied. This is a problem if you are shooting with BUIS (which I do, occasionally). Additionally, the barrel nut is smooth with no knurling, with the rail is attached to the nut simply by a plate behind the nut that screwed into the rail... without anything providing additional friction to prevent it from rotating. Without knurling, I can definitely see how the rail could rotate on the nut.
In addition to the problems this would generate for your BUIS' zero, the tight tolerances inside the rail could also cause the rail to no longer be truly free floated, since the rail may contact the gas block. I have a BCM lo-pro gas block under my rail, and it wouldn't take much rotation for the rail to touch it.
And, if you make the ill-advised decision to bridge the gap between the receiver and the rail with your scope mount, this could cause the scope to be thrown off zero, as well.
BCM's anti-rotation solution seems superior here, in that the tabs are actually more "fitted" to the upper receiver. But I don't know how tough they are, so don't take my word for this.
Honestly, I don't think this would affect function and I'm not going to swap out my rail anytime soon, but, in retrospect, I probably should have purchased a rail that allowed me to keep my front sight post. This post is NOT a dig at DD, and I will continue to purchase DD products in the future with confidence. BUT, if you shoot with BUIS from time to time, I definitely encourage you to keep your FSP.
This post is NOT a dig at DD. If you want to attack DD, go elsewhere.
Agreed in 100%. I was honestly surprised by what happened. I was expecting more damage to the rail itself - obviously that didn't happen, rail took a beating very well. However rail shift was real and it would totally screw your iron sights zero.
I'm finally back home today so i could take rifle apart and check what happened. Both screws on the right side were lose, also upper screw on the left side was lose as well.
Lower bottom screw was still sitting extremely tight, but that didn't matter, since the whole "ring" shifted anyhow.
I have used now blue loctite - we will see if this will hold rail in place...
http://www.akoperatorsunionlocal4774.com/wp-content/uploads/2016/11/DD1small.jpg
I've always used blue thread locker, and haven't had any rotation problems with my DD SlimRail 12.0 or Lite Rail III 12.0. In fact, I shot my LRIII again today at lunch (also taken to the range Thursday and yesterday). No appreciable rotation or concern.
I did have issues with my (now sold) DD MFR 12.0. I had to remove the MFR and reinstall (while re-loctiting and exceeding the recommended torque on each screw). This seems to have fixed the problem, but I probably only ran another 500 rounds through the Colt with the reinstalled tube prior to selling the whole rig.
Nocalsocal
11-07-16, 14:37
Robski was the rifle purchased as a whole or put together? As in the rail was installed by someone other than Daniel Defense. If so I would be annoyed that it left the manufacturer that way. After all it doesn't really qualify as a budget rifle.
Sent from my SM-G935V using Tapatalk
The MFR uses a completely different locking arrangement so it isn't relevant to SR concerns:
42301
Robski was the rifle purchased as a whole or put together? As in the rail was installed by someone other than Daniel Defense. If so I would be annoyed that it left the manufacturer that way. After all it doesn't really qualify as a budget rifle.
Sent from my SM-G935V using Tapatalk
Rifle was purchased as a whole. No mods were done to it, other than adding optics or iron sights.
I guess lesson here is, every time you have new rifle, no matter who the manufacturer is, just take it apart and tight all the screws by yourself.
Hope to hear something from DD soon...
Jwknutson17
11-08-16, 09:57
If you did this to a KMR it would have smashed in the sides and would be much more usless with irons then the DD.
Maybe the KMR wouldn't have rotated right at the rail, but it would be most likely touching the barrel where it took the impacts further down the rail. Or at least made the irons completely useless also.
Like you said. This is where fixed front posts have their advantages.
Im not really sure about that. My KMR seems pretty robust. I have about 5000 rounds through that gun with no ill effects. I am not about to go try to break it though lol
If you did this to a KMR it would have smashed in the sides and would be much more usless with irons then the DD.
Maybe the KMR wouldn't have rotated right at the rail, but it would be most likely touching the barrel where it took the impacts further down the rail. Or at least made the irons completely useless also.
Handled being dropped fine.
https://www.youtube.com/watch?v=eQYV96hHoGU
Jwknutson17
11-08-16, 12:42
I have had much different results with KMRs on a few rifles. Not getting into specifics or bashing/praising one company or another. From my personal experience I no longer run KMR rails on any rifles. I'm sure they work great for some, just not for me.
lawusmc0844
11-08-16, 13:27
Rob Ski, keep up the great work!
Now I think about it, I remember the first gen DDM4V1 I bought back in 2009 had its Omega X FSP rail a little loose after a few hundred rounds, and this was a factory gun. I took a tiny hex key and tightened it back up without loctite and it didn't give me any problems the time I owned the rifle. My BCM BFH midlength rifle has an Omega rail installed as well with 10800rds through it. Recently I noticed POI shift to the left despite that never happening before as its supposed to be a free float but getting back home I checked the set screws to find some of them loose. I am still a big fan of the older Omega quad rails except for the tiny set screws they use, but not a problem blue loctite wont fix.
Singlestack Wonder
11-08-16, 13:39
Proves once again that FSB's should be used for serious rifles, not rail mounted sights....
Thanks for the info, guys. To be honest, my favorite and most used rail is the DD LITE III (DDM4). I run that thing on multiple uppers. My sample size of 3 has shown the rail to be very robust/rigid/reliable/predictable. However, I did use loctite on my bolts.
I gotta say, i was a bit surprised by the above mentioned test results.
Thanks to rob ski for doing to his rifles what i will not/cannot do to mine. Id be interested to see the test results after loctite has set up on the very same bolts.
Well just as an additional data point, I checked the bolts on my new v7 check a few minutes ago while installing some rail covers and both the ones on the right side and the top left side one were loose. I have not had an opportunity to shoot the rifle yet so I'm sure it came this way from the factory. I tightened them but do not know what the proper torque should be and, unfortunately, don't have a torque driver at any rate. . Very concerning to say the least.
As was stated in the OP, For the price, which is certainly considerable for someone of my meager means, and considering the DD reputation, I expected better.
Having a great warranty is nice and we will take care of is great but it's also a weak retort to what has turned out to be a limited but obviously not totally isolated issue. However true the "most people mount an optic" statement is, quite frankly, irrelevant. The bolts should not be loose, period. YMMV
Mrgunsngear
11-11-16, 14:58
Proves once again that FSB's should be used for serious rifles, not rail mounted sights....
I'm sure there are some rails that are strong enough but it's always a strength vs. weight thing. Engineering helps but only so much.
#FSBMafia
I think the bolts being loose is the driving factor here.
Just an update:
I email DD regarding the bolt looseness and received a reply almost immediately. I was advised
DO NOT use loctite ( Although I would not think blue loctite would be an issue)
There is no torque value, Just "Hand tight".
Mr. Brown also offer to send me a label to ship the rifle back if I felt it was needed.
I'm undecided on shipping it back based on th fact I've already done as the email reply advised.
I do think that the response time from DD was excellent!
Nocalsocal
11-11-16, 17:11
Nice customer service. But having no torque value is rather disturbing. Blue loctite is better than a loose handguard. Come on Daniel Defense I would think there's more to it than "hand tight "!?
Sent from my SM-G935V using Tapatalk
Nice customer service. But having no torque value is rather disturbing. Blue loctite is better than a loose handguard. Come on Daniel Defense I would think there's more to it than "hand tight "!?
Sent from my SM-G935V using Tapatalk
Agreed. I have gone from feeling great about my decision to buy to being quite puzzled. :confused:
Maybe people won't agree with me but I think checking all hardware and tightening bolts and screws is just part of preventative maintenance even if it's straight from the factory. I'm definitely interested in how this goes with the DD hand guard since I am current deciding on one for a middy that's going to see hard use.
Singlestack Wonder
11-12-16, 11:11
Maybe people won't agree with me but I think checking all hardware and tightening bolts and screws is just part of preventative maintenance even if it's straight from the factory. I'm definitely interested in how this goes with the DD hand guard since I am current deciding on one for a middy that's going to see hard use.
This....if the rifle is for serious use, it's up to the user to double check all of its systems before utilizing the rifle in a shtf situation.
Several rails being manufactured do not have a recommended torque value, so I am not sure why people are acting as of the Book of Revelations was just revealed. I use blue Loctite on almost all screws that secure rails and optics. The exception are those that use helicoils.
For years we have always recommended that the end user check his weapon and do an inspection.
I don't understand why DD advised against Loctite unless removing the Loctite applied part would damage something. As a novice, I'm curious.
I don't own any of the new DD rails, but I believe the plate is aluminum. Maybe it is exactly as IG said and the plate has helicoils.
What's old is new again, pinned FSB's have always had lots of proponents on this forum and others.
I have a DD V11 and it is my only firearm. I will not be dropping it anytime soon. I know DDs are built like tanks, but I am a little bit disappointed that that one's rail shifted after so little abuse when you consider the torture test that they did with Larry Vickers.
Guys, to make it clear, when I started using this rifle, bolts were not lose. They were all tight.
They didn't become lose from recoil either. Many rounds went down the pipe on that rifle prior drops on concrete and rail was holding up. Bolts went lose after drops only.
I have them on blue loctite now and so far I haven't noticed any shifts.
Nocalsocal
11-13-16, 11:43
Guys, to make it clear, when I started using this rifle, bolts were not lose. They were all tight.
They didn't become lose from recoil either. Many rounds went down the pipe on that rifle prior drops on concrete and rail was holding up. Bolts went lose after drops only.
I have them on blue loctite now and so far I haven't noticed any shifts.
Thanks for the clarification and great channel btw!
Anybody have any idea why DD doesn't recommend any threadlocker? Or any confirmation on the use of helicoils or other methods?
Sent from my iPad using Tapatalk
justin_247
11-13-16, 12:07
Guys, to make it clear, when I started using this rifle, bolts were not lose. They were all tight.
They didn't become lose from recoil either. Many rounds went down the pipe on that rifle prior drops on concrete and rail was holding up. Bolts went lose after drops only.
I have them on blue loctite now and so far I haven't noticed any shifts.
Just to double-check, did only the rail shift or did the entire barrel nut shift?
Just to double-check, did only the rail shift or did the entire barrel nut shift?
Justin, only rail moved. DD is using separate little bracket which is holding bolts and it is isolated from the barrel nut to some degree.
http://www.akoperatorsunionlocal4774.com/wp-content/uploads/2016/11/DD1small.jpg
I don't own any of the new DD rails, but I believe the plate is aluminum. Maybe it is exactly as IG said and the plate has helicoils.
Iraqgunz did not state the DD rail uses helicoils. He was referring to different manufacturers' rail systems that use helicoils.
Not sure if the DD bolt up plate is steel or aluminum, but i know the barrel nut is steel.
Justin, only rail moved. DD is using separate little bracket which is holding bolts and it is isolated from the barrel nut to some degree.
http://www.akoperatorsunionlocal4774.com/wp-content/uploads/2016/11/DD1small.jpg
Hi Robski,
Did you see any reason not to loctite the bolts? Also, did you put the loctite on the entire bolt thread length?
Thanks
Hi Robski,
Did you see any reason not to loctite the bolts? Also, did you put the loctite on the entire bolt thread length?
Thanks
Yes, I do have blue loctite on bolts now, but I put it only on the tip of bolts (just a tip - lol), enough to get that blue color on threads.
I honestly don't see reason for not using blue loctite here, unless I'm missing something.
bowman57_2
11-15-16, 10:32
Yes, I do have blue loctite on bolts now, but I put it only on the tip of bolts (just a tip - lol), enough to get that blue color on threads.
I honestly don't see reason for not using blue loctite here, unless I'm missing something.
Are you planning on doing another drop test now that the bolts have loctite on them?
Are you planning on doing another drop test now that the bolts have loctite on them?
Yes! I'm sorry, but DD has to do it again! :-)
Yes! I'm sorry, but DD has to do it again! :-)
Cool! Looking forward to it soon!
bowman57_2
11-26-16, 02:20
Any updates on the drop tests?
Any updates on the drop tests?
I'm splitting vepr and DD now into the separate, 5k rds tests. In first episode of DD 5k run, i will repeat drop tests.
RetroRevolver77
11-26-16, 09:30
I'm splitting vepr and DD now into the separate, 5k rds tests. In first episode of DD 5k run, i will repeat drop tests.
Are you going to use the exact same rifles or try new rifles?
7n6
Are you going to use the exact same rifles or try new rifles?
7n6
Same rifles. Lol, I can't afford to keep buying new ones every time...
bowman57_2
12-01-16, 09:27
Probably a stupid question but is the bolt up bracket being held on the upper just by being pinched between the upper and bbl nut? It doesn't seem like it would be very secure mounting system if it's just relying on that and the small anti-rotation tabs to keep the rail from moving. Am i missing something?
bowman57_2
12-01-16, 09:32
I forgot the gas tube runs through the bracket too but it still doesn't seem as solid as I always thought it was.
justin_247
12-01-16, 16:35
I forgot the gas tube runs through the bracket too but it still doesn't seem as solid as I always thought it was.
No, the rail and bracket "pinch" the barrel nut. The bracket is actually loose between the barrel nut and the upper when you don't have the rail attached.
bowman57_2
12-01-16, 18:03
No, the rail and bracket "pinch" the barrel nut. The bracket is actually loose between the barrel nut and the upper when you don't have the rail attached.
How does the bracket stay loose when the bbl nut is tight on the upper? What holds the bracket in place if its not being pinched between the upper and bbl nut?
justin_247
12-01-16, 18:58
How does the bracket stay loose when the bbl nut is tight on the upper? What holds the bracket in place if its not being pinched between the upper and bbl nut?
I strongly suggest you read the installation guide:
https://danieldefense.com/files/Web/DD-AR15_Lite_Rail_III.pdf
bowman57_2
12-01-16, 19:31
Maybe I'm just a little slow today but I still don't see how the bracket is able to move if the barrel nut is tight on the upper. Maybe I should just give up on understanding it and just accept that it works lol
It's a little hard to explain without showing you. The bolt up plate is not sandwiched between the barrel nut and the receiver. The barrel nut inserts through the plate.
Sent from my SM-G920V using Tapatalk
bowman57_2
12-01-16, 21:51
I've wanted one of the DDM4 rails for a long time but other stuff always got in the way and now I don't really know if I still want one. My work rifle has a RIS II on it and I've beat the living hell out it and it has always just came back asking for more, and theres been plenty of guys before me that have done the same to that same gun. I know the RIS has 2 more mounting screws, but I don't see how 3 small drops could knock this rail off center and my RIS is still going strong.
justin_247
01-14-17, 10:40
Rail shifted again in AKOU's tests, despite having been reinstalled with Loctite.
https://youtu.be/vHEG0dtfwq4?t=3m21s
Pretty disappointing. My v5 has zero rail shift after 8000 rds, then again I don't use it as a club.
justin_247
01-15-17, 11:34
Pretty disappointing. My v5 has zero rail shift after 8000 rds, then again I don't use it as a club.
Yup, no problems here, either (I use the Lite III, but it has the same attachment method).
I just think it's important to highlight this problem to encourage DD to develop a more durable attachment system. The rail is amazing, but the attachment system brings it down quite a few levels.
Over on the ak files Rob stated that he will be meeting up with them a SHOT
jackblack73
01-15-17, 13:19
Pretty disappointing. My v5 has zero rail shift after 8000 rds, then again I don't use it as a club.
He didn't use it as a club either. Just dropped it multiple times. Nothing too aggressive or unlikely to happen.
Torquetard
01-15-17, 13:23
The reason DD advises against using loctite in the screws is because they will strip if you aren't careful. Hand tight is fine, but any harder than that and your hex bit will all of a sudden be spinning when the screw isn't..
ODgreenpizza
01-15-17, 13:50
If I had a rotation issue with one of these rails the following would be my "maximum effort" re-install procedure:
1. Chase threads in rail w/ screws to reduce chance of imperfect thread engagement
2. Thoroughly degrease screw threads, hole threads, exterior of bbl nut, any surface of rail and bolt up plate that contacts bbl nut
3. Apply thread locker to screw threads
4. Install rail with screws finger tight then torque to mfr req spec of 32 in/lbs in diagonally opposed sequence
It seems uniform clamping force between rail, plate, and bbl nut is crucial for preventing rotation in this design. Longer rails and rails with lots of stuff mounted may be more prone to rotation.
I'm not sure why DD would say to avoid using loctite on the screws. I just checked my DDM4A1's rail screws and they all had factory-applied thread locker on them. None were loose, but then again I haven't dropped my gun on concrete.
I hope we will hear something from DD on this. I figured I was close to golden buying DD.
justin_247
01-16-17, 10:05
I hope we will hear something from DD on this. I figured I was close to golden buying DD.
DD is still good to go. The rifle performed fine, even when the rail rotated. If irons aren't your primary optic, this isn't really much cause for concern.
I've come around to the opinion that all "hard use" rifles need to have a fixed front sight post on it, or a seriously heavy duty rail like a DD RIS II or Geissele rail.
DD is still good to go. The rifle performed fine, even when the rail rotated. If irons aren't your primary optic, this isn't really much cause for concern.
I've come around to the opinion that all "hard use" rifles need to have a fixed front sight post on it, or a seriously heavy duty rail like a DD RIS II or Geissele rail.
Yeah. That's why I have my 6920. Can't afford a RIS II but may look into putting a Geissele on the DD M4v7 if that's doable.
They replaced 6 large screws with 4 small screws. Smaller/lighter on the same exact design means weaker.
The best anti-rotation is the Geissele set screw style IMO.
I also think the kmr has a great design.
DD is still good to go. The rifle performed fine, even when the rail rotated. If irons aren't your primary optic, this isn't really much cause for concern
Negative. Multiple FTF before fixing itself
putting blue loctite on the 4 screws won't solve a thing. What is "shifting" is the plate the rail attaches to and it is held in place by the bbl nut. You can only tighten that nut so much. Perhaps they should have rough textured the nut and the plate to keep it from shifting .? The V9 attaches the same way does it not? the new V7 attaches completely differently.
I thought the new v7 used the same mounting system as the ddm4 rail that is used on the v9 and the v5
I thought the new v7 used the same mounting system as the ddm4 rail that is used on the v9 and the v5
If anyone knows, I'm very interested to hear if this is the case.
The NEW V7 does away with the bbl nut....... look at a pic of one there is a plate that attaches to the bbl/extension, which is held by the rail system , there is no bbl nut.
they adopted this from the 308 M5 which uses the same system as the NEW V7.
from DD's website
Innovative 4-bolt connection system utilizing a unique barrel extension securely attaches free-floating CHF barrel and KeyMod handguard mounts securely to upper without barrel nut
The NEW V7 does away with the bbl nut....... look at a pic of one there is a plate that attaches to the bbl/extension, which is held by the rail system , there is no bbl nut.
they adopted this from the 308 M5 which uses the same system as the NEW V7.
from DD's website
Innovative 4-bolt connection system utilizing a unique barrel extension securely attaches free-floating CHF barrel and KeyMod hand guard mounts securely to upper without barrel nut
This is incorrect, the DD5V1 (308) has a flange machined into the barrel where as the MFR XS (new v7 rail) uses a standard barrel nut much like the DDM4 Rail (V9,V5) I have sent a message to Joe Marler on AR15.com asking him how the 2 rails differ in mounting.
putting blue loctite on the 4 screws won't solve a thing. What is "shifting" is the plate the rail attaches to and it is held in place by the bbl nut. You can only tighten that nut so much. Perhaps they should have rough textured the nut and the plate to keep it from shifting .? The V9 attaches the same way does it not? the new V7 attaches completely differently.
The plate is loose on the Lite Rail/RIS II/DDM4/MFR XS. The way the rail is held in place is the clamping force on the front and rear of the barrel nut at the same time by the screws. If it is shifting, it is because the clamping force isn't enough to keep it from shifting. Texture might help though.
This is incorrect, the DD5V1 (308) has a flange machined into the barrel where as the MFR XS (new v7 rail) uses a standard barrel nut much like the DDM4 Rail (V9,V5) I have sent a message to Joe Marler on AR15.com asking him how the 2 rails differ in mounting.
Please let us know if he replies.... and thanks!
jackblack73
01-18-17, 13:47
The plate is loose on the Lite Rail/RIS II/DDM4/MFR XS. The way the rail is held in place is the clamping force on the front and rear of the barrel nut at the same time by the screws. If it is shifting, it is because the clamping force isn't enough to keep it from shifting. Texture might help though.
I've been trying to figure out how that system works. Is the only clamping force on the front and rear of the barrel nut? If so, I could see how it would be less resistant to twisting than a rail that clamps onto the entire surface area of the barrel nut. Is there any other provision made to prevent rotation? From what I've seen most rails that have tabs to prevent rotation usually have a little space between the tabs and the receiver. So while they will prevent extreme rotation they won't prevent small movement. It seems like the DD rails are designed more to prevent a rail from being pulled off than to prevent rotation.
I've been trying to figure out how that system works. Is the only clamping force on the front and rear of the barrel nut? If so, I could see how it would be less resistant to twisting than a rail that clamps onto the entire surface area of the barrel nut. Is there any other provision made to prevent rotation? From what I've seen most rails that have tabs to prevent rotation usually have a little space between the tabs and the receiver. So while they will prevent extreme rotation they won't prevent small movement. It seems like the DD rails are designed more to prevent a rail from being pulled off than to prevent rotation.
Correct. They have two nubs on each side of the receiver. The type of "anti-rotation" tab that these rails have (including the RIS II) will only prevent the rail from completely unscrewing. It may cant, but the rifle will still function. Now, at least on the first instance, AKOU's most definitely was not the barrel nut turning but the rail moving on the barrel nut since the screws were loose. When the rail is loose, it can not only rotate but can move in all directions a slight amount.
The v7 uses th same system as the v11 other than the back of the rail is a little shorter and a spacer goes between the rail and the mounting plate. If the bolts are tight its making contact with front and back of the barrel nut. I don't think it would be easy to rotate, and if it did it couldn't rotate very much.
They replaced 6 large screws with 4 small screws. Smaller/lighter on the same exact design means weaker.
The best anti-rotation is the Geissele set screw style IMO.
1+
I had HDSI upper with rare 13" Geissele SMR keymod mk4 handguard I love that handguard, I would align the Handguard to upper using set screw on bottom one on each side and after its tight and aligned I would further tighten them while holding alignment so the set screw bite into bottom of upper preventing rotating for I was planning on treating it just like my other rifles.
kinda hard.
I had to sell it before I could really use it and if I had use it it would quickly accumulate marring, dent, yadada.
Geissele smr is one of few ff handguard i would trust for hard use.
justin_247
02-29-20, 13:10
Not to reopen an old thread, but I felt this was the most appropriate place for it.
I noticed that DD now seems to be shipping a different type of screw for their DDM4 rails and the threads appear slightly more coarse (although this could be some kind of photo or compression distortion):
OLD VERSION https://www.ar15goa.com/product/ddm4-rail-slim-rail-ar15-lite-rail-iii-screw-pack-by-daniel-defense/
https://www.ar15goa.com/wp-content/uploads/2019/03/ddm4_screwpack_01-134-81677-2.jpg
NEW VERSION https://danieldefense.com/screw-pack.html
https://danieldefense.com/media/catalog/product/cache/35b7b51f50634a4c237a5fa33533d8cc/r/a/rails_screw_pack_01-134-81677.jpg
Has anybody had a chance to try these?
That new version is like what the RISII has always had.
This is whole bunch of unnecessary drama to have the cosmetic appearance of a continuous top rail.
The old locking collar was a better method than pretty much anything new.
The only new rails I like are the BCMs.
Marler5811
03-05-20, 08:06
Not to reopen an old thread, but I felt this was the most appropriate place for it.
I noticed that DD now seems to be shipping a different type of screw for their DDM4 rails and the threads appear slightly more coarse (although this could be some kind of photo or compression distortion):
OLD VERSION https://www.ar15goa.com/product/ddm4-rail-slim-rail-ar15-lite-rail-iii-screw-pack-by-daniel-defense/
https://www.ar15goa.com/wp-content/uploads/2019/03/ddm4_screwpack_01-134-81677-2.jpg
NEW VERSION https://danieldefense.com/screw-pack.html
https://danieldefense.com/media/catalog/product/cache/35b7b51f50634a4c237a5fa33533d8cc/r/a/rails_screw_pack_01-134-81677.jpg
Has anybody had a chance to try these?
Same Thread Pitch. Larger Hex. Transitioned from a 2.5mm to a 3mm.
justin_247
03-08-20, 09:34
Same Thread Pitch. Larger Hex. Transitioned from a 2.5mm to a 3mm.
Thanks for the reply!
trinitynzxt
01-20-21, 15:29
Is this still an issue. My DDM4 V7 LW complete upper just arrived via ups today and now I'm wondering if I should just try to sell it / return it after reading about this and people getting DD rifles and uppers with screws loose and having issues zeroing iron sights due to the handguard issues.
Is this still an issue. My DDM4 V7 LW complete upper just arrived via ups today and now I'm wondering if I should just try to sell it / return it after reading about this and people getting DD rifles and uppers with screws loose and having issues zeroing iron sights due to the handguard issues.
This is your first post on this site, and right above your post is the DD rep, I would reach out to him.
trinitynzxt
01-20-21, 15:40
This is your first post on this site, and right above your post is the DD rep, I would reach out to him.
Not to be rude, but would kind of like to hear from the community. I can't imagine a rep saying yea we got rail problems don't buy our stuff.
Leonidas24
01-20-21, 18:09
Is this still an issue. My DDM4 V7 LW complete upper just arrived via ups today and now I'm wondering if I should just try to sell it / return it after reading about this and people getting DD rifles and uppers with screws loose and having issues zeroing iron sights due to the handguard issues.
So you just got the upper today and want to sell it or return it? Have you even shot it yet?
Not to be rude, but would kind of like to hear from the community. I can't imagine a rep saying yea we got rail problems don't buy our stuff.
So I have a V5 from '12 and a V7 upper from '17 or early '18, if you just got this today doesn't mean you are going to have a problem and if you do, the rep is on this board to correct any issue. You just got this, shoot the piss out of it and if there is an issue bring it to the boards attention otherwise your more then likely fine. I've had issues with my DDM4V5, a BCM upper, and an ADM lower ( I won't go into what I ordered from PSA) all of them took care of the issue. You're more then likely fine, but I've seen a $2100 Triarc fail at a class, its a machine and machines break. Keep your head up and congrats on your new upper.
So you just got the upper today and want to sell it or return it? Have you even shot it yet?
That's how I read it.
trinitynzxt
01-20-21, 20:39
That's how I read it.
Why shoot it if there are problems with it, easier to sell unused, and if I cant sell it, I could still return it. Getting very off track to the question at hand however. Also, it would have been cool for $1200 if they could have included an allen key long enough to attach the fore grip.
Why shoot it if there are problems with it, easier to sell unused, and if I cant sell it, I could still return it. Getting very off track to the question at hand however. Also, it would have been cool for $1200 if they could have included an allen key long enough to attach the fore grip.
What's wrong with it? Are the screws loose?
El Vaquero
01-21-21, 19:08
They’ve changed the screws they use and also now use loctite. You shouldn’t have a problem.
They’ve changed the screws they use and also now use loctite. You shouldn’t have a problem.
When?? I’m wondering if I need take apart my V11 with 15” slim rail. Then again, I don’t treat it like a truck gun like certain “union” operators, lol.
El Vaquero
01-21-21, 22:00
They changed a couple years ago I believe. If you go on their website and look under spare parts section it will have a picture of the newer design. All the changed was the shape of the head I believe. The old style was dome like and the new style is no longer tapered and right angled. Allows for more material where the hex wrench bites into it. I know, terrible description but hard to describe without pics.
They changed a couple years ago I believe. If you go on their website and look under spare parts section it will have a picture of the newer design. All the changed was the shape of the head I believe. The old style was dome like and the new style is no longer tapered and right angled. Allows for more material where the hex wrench bites into it. I know, terrible description but hard to describe without pics.
I have the old dome heads. My rifle is from ca 2015. I’m hesitant to touch them and strip them. Thus creating a problem I didn’t have before.
I’ll touch it if it moves. In the meantime, an optic rail that bridges the handguard might be nice insurance against rotation.
I have the old dome heads. My rifle is from ca 2015. I’m hesitant to touch them and strip them. Thus creating a problem I didn’t have before.
I’ll touch it if it moves. In the meantime, an optic rail that bridges the handguard might be nice insurance against rotation.
I've got a V5 from 2012, and I've never seen this issue, and while I wouldn't say that I miss treated the rifle, I have already replaced the gas rings, and it has been my go to rifle and a workhorse for classes. It has been dropped few times, and fallen over a few times as well and I haven't noticed any rotation. All that being said, when I bought the rifle, the stock was canted slightly and the staking on the castle nut was poor, a gunsmith corrected this for me a month or so after purchase.
El Vaquero
01-22-21, 07:51
I’d buy a set or two of the new screws and just have them on the ready in case you need to replace your gas tube or they loosen up.
When mine loosened I was running the gun hard. It was very hot (the rifle and the weather) and I was banging it into barricades. And it wasn’t my first time abusing it.
I’m not happy it happened at all (don’t feel it should have) but it did. But since replacing the screws I’ve run it hard since and abused it with no movement.
I’d witness mark the screws as added security to make it easier to see if they start moving.
Leonidas24
01-22-21, 20:26
Why shoot it if there are problems with it, easier to sell unused, and if I cant sell it, I could still return it. Getting very off track to the question at hand however. Also, it would have been cool for $1200 if they could have included an allen key long enough to attach the fore grip.
How are you going to know there are problems if you don't shoot it? It's not worth worrying about when there are thousands upon thousands of DD rifles, uppers, and handguards out in peoples' hands that haven't experienced this problem. It's better to shoot it and address the issue in the unlikely event that it arises. If it really bothers you go to Lowe's and buy some Loctite 242 and apply it to the fasteners yourself for cheap insurance.
Powered by vBulletin® Version 4.2.5 Copyright © 2024 vBulletin Solutions, Inc. All rights reserved.