View Full Version : Is the KAC URX II combat viable?
SW-Shooter
11-02-11, 18:50
I've read some musings that it is fragile. Is it viable for seriously hard combat use?
I was wondering the same thing.
I want a super strong rail.
Centurion is what I think Im going with
There was some ancedote stuff about barrel nuts coming loose.
If you want something "combat" tough, the DD RIS-II has a NSN attatched to it as is extremely solid. Not that the Army buys only the best things in every circumstance, but it is my understanding the RIS-II went through a testing process and came out on top. There was an article on Gear Scout about it.
Noveske's SWS rail appears to be pretty darn solid as well. I think the rail is pinned to the MUR uppers which sounds pretty damn solid.
The SWS rails are heavy though.
Magic_Salad0892
11-02-11, 19:20
I'd go with KAC URX III, DD, or Centurion over anything else on the market right now.
Has anyone used the ARMS S.I.R?
That thing is almost 4 bills.
I would imagine its pretty tough
Has anyone used the ARMS S.I.R?
That thing is almost 4 bills.
I would imagine its pretty tough
I didn't think anyone put ARMS and tough in the same sentence unless they were joking.
Cost is not synonymous with quality.
Noveske's SWS rail appears to be pretty darn solid as well. I think the rail is pinned to the MUR uppers which sounds pretty damn solid.
The SWS rails are heavy though.
I have to agree, mine definitely exceeded my expectations.
At least compared to other rails I've used.
Belmont31R
11-02-11, 19:47
I've read some musings that it is fragile. Is it viable for seriously hard combat use?
Its used on the SR25 (same setup just a little bigger) M110, Mk11, and is used by the Secret Service at the White House and protection details.
The only thing Ive seen is the front sight snapping off on some M110's but soldiers can destroy anything.
I did have one come loose but I don't think it was installed properly with thread locker on the barrel nut. Both of my KAC factory guns have not had any rail issues. 18k rds through my SR15 and 3300 through my EMC. If it were ever a possibility I would not hesitate to use one in a deployment.
That said I think the DD RIS II is a more solid rail and allows for more user preference. The RIS II has anti rotation tabs (the Lite rails do not unless they recently added them) which the URX does not.
GermanSynergy
11-02-11, 19:55
Absolute garbage.
Has anyone used the ARMS S.I.R?
That thing is almost 4 bills.
I would imagine its pretty tough
Belmont31R
11-02-11, 20:02
Absolute garbage.
Agreed. One of the first rails I bought before I knew better. Around 2006 or so.
The SIR is junk, and I speak from experience. I have an SR15 upper, my only reservation is the flip front sight. My preference is for LaRue rails though.
That said I think the DD RIS II is a more solid rail and allows for more user preference. The RIS II has anti rotation tabs (the Lite rails do not unless they recently added them) which the URX does not.
Sorry for the thread drift, but I was wondering if there have been any cases of the DD lite rails rotating? With a rail system as seemingly solid as the lite series do you think that anti-rotation tabs are necessary?
jonconsiglio
11-02-11, 20:19
I have broken two front sights, one needing replaced. Not a big deal, but it happeneded. Then, I had a barrel nut come loose. I could squeeze the side rails towards each other and they'd show flex.
What does any of this mean? I have no clue, just giving my experience. Luckily I sold them, one to a sucker by the name of David, a member here! (I PM'd you back twice!)
I had a LW URX II and never mounted it then played around with my buddy's URX III rifle length and it doesn't seem as sturdy as the URX II, but it's also longer with less support on the side rails due to the thinner profile. Again, not a big deal, it just doesn't have the same feel as some other, more robust designs. At the same time, I really like the profile of both, the URX III having a slight edge.
Most likely that flex is a good thing as a hard impact will be partially absorbed by the flex instead of it all being sent straight to the barrel nut.
But, I should stress that a little bit of flex and broken front sights mean nothing when it comes to the top rail holding zero for your laser and the mount itself not coming completely loose. It would have been nice though if the URX II was rotation limited.
I have two Daniel Defense RIS II's and they seem bombproof. What I prefer about them is even though they're also a two piece design, the front of the rail has a solid piece that supports the side rails.
Please understand I'm not bashing the URX rails in any way, I'm just stating my experience with them. Nothing is perfect and there's a trade off for everything. A URX III without an integrated front sight would be high on my list for my 18" precision rig whenever I get around to it. I believe the one for one of the blackout's has a complete rail without the front sight. That would be great in rifle length.
Sorry if I flip flopped there. I put one of them through a lot of abuse and it kept going strong where lesser rails would likely have bent or broke.
Belmont31R
11-02-11, 20:23
Sorry for the thread drift, but I was wondering if there have been any cases of the DD lite rails rotating? With a rail system as seemingly solid as the lite series do you think that anti-rotation tabs are necessary?
I don't recall ever hearing of a Lite rail rotating but DD either had reason to or did it just as an extra selling point. Either way it doesn't hurt to have them as an extra layer of weapon ruggedness.
Belmont31R
11-02-11, 20:30
I have two Daniel Defense RIS II's and they seem bombproof. What I prefer about them is even though they're also a two piece design, the front of the rail has a solid piece that supports the side rails.
On another site a poster bent the bottom rail of a RIS II after shooting with a bi pod and leaning into it. The bottom rail towards the front bent downwards slightly (maybe 3/16ths). DD replaced it of course but Im not sure if they had any design changes. Im not sure if he had the screws in properly because that part of the rail is supported by the screws right at the front.
Maybe thats one situation in which a one piece rail might have some merit. I generally dislike 1 piece rails because I like to take an oily rag to the barrel for rust prevention.
Eh... spray paint doesn't rust.
davidjinks
11-02-11, 20:36
I don't care who you are...that shit's funny! A sucker born every minute!
So far, I like the URX II. I haven't used it "hard" yet but I don't think there would be any issues. Now, if you don't know a thing about weapons and how they work (Jon) then I guess you could break things...
The SR15 that I just got is pretty frickin awesome. Again, I haven't run it hard but I can't see where it could fail. As long as I'm not using my rifle as a hammer...
Plus, as a civilian, I'm hoping I never have to be in combat.
I have broken two front sights, one needing replaced. Not a big deal, but it happeneded. Then, I had a barrel nut come loose. I could squeeze the side rails towards each other and they'd show flex.
What does any of this mean? I have no clue, just giving my experience. Luckily I sold them, one to a sucker by the name of David, a member here! (I PM'd you back twice!)
I didn't think anyone put ARMS and tough in the same sentence unless they were joking.
Cost is not synonymous with quality.
I have never actually seen one in person.
I thought they were the "Elite" rail lol hahaha
Belmont, sorry you got fooled into it. That sucks losing that much money on a garbage product. I would be pretty pissed too.
I know NOTHING about that rail other than I hate the "piggyback" the upper design and its expensive as hell.
Sorry for the hijack there
Belmont31R
11-02-11, 20:43
I have never actually seen one in person.
I thought they were the "Elite" rail lol hahaha
Belmont, sorry you got fooled into it. That sucks losing that much money on a garbage product. I would be pretty pissed too.
I know NOTHING about that rail other than I hate the "piggyback" the upper design and its expensive as hell.
Sorry for the hijack there
I sold it for almost as much as I paid...:cool:
I sold it for almost as much as I paid...:cool:
Oh sweet! It worked out then.
Man I bet it was scary though. Did you realize they suck as soon as you opened it or later on.
Is it the material or the mounting system?
Belmont31R
11-02-11, 20:59
Oh sweet! It worked out then.
Man I bet it was scary though. Did you realize they suck as soon as you opened it or later on.
Is it the material or the mounting system?
They are heavy and large. Keep in mind it was one of the first rail designs to come out...but they have not really changed in a decade. For a carbine around the same time you could get KAC RAS's which are much easier to install and are not ****in huge.
Generally Im not an ARMs fan and that is through personal use of their products. I bought other stupid shit from them like BUIS and optic mounts. Everything I have used theirs is not as well designed or as good of quality as their competitors. They also donate to anti gun politicians like Martha Coakley in MA. Im convinced the only reason they are still in business in military contracts they get. I hardly ever see their stuff on civilian guns. A lot of suckers out there though (Im a reformed sucker ;)). Their mounts I had were so bad you had to use a pry tool to loosen the lever and Im lucky none of them ever snapped off. One rail it would be loose and you could move the mount around and another was so tight the pry bar came out.
jonconsiglio
11-02-11, 21:10
On another site a poster bent the bottom rail of a RIS II after shooting with a bi pod and leaning into it. The bottom rail towards the front bent downwards slightly (maybe 3/16ths). DD replaced it of course but Im not sure if they had any design changes. Im not sure if he had the screws in properly because that part of the rail is supported by the screws right at the front.
Maybe thats one situation in which a one piece rail might have some merit. I generally dislike 1 piece rails because I like to take an oily rag to the barrel for rust prevention.
I recall reading that somewhere, I think... I'm with you on the ability to remove a bottom rail though, I prefer it in the salty climate here...
Wow.
I usually take with a grain of salt what I hear about products.
Things like you describe remove all doubt for me. Thanks for the info.
I knew NOTHING about the rail except for the website and the military contracts, If you look at it like that, they appear to be super elite like I said haha.
Even like you said, "You hardly ever see them on civilian guns", which makes you think that they MUST be badass.
I appreciate you guys filling me in on that, just in case someone ever tries pawning one off on me.
Thank you
jonconsiglio
11-02-11, 21:13
I don't care who you are...that shit's funny! A sucker born every minute!
So far, I like the URX II. I haven't used it "hard" yet but I don't think there would be any issues. Now, if you don't know a thing about weapons and how they work (Jon) then I guess you could break things...
The SR15 that I just got is pretty frickin awesome. Again, I haven't run it hard but I can't see where it could fail. As long as I'm not using my rifle as a hammer...
Plus, as a civilian, I'm hoping I never have to be in combat.
Don't worry dude, my guess after our conversations is you don't run anything hard, so a Lego hand guard would likely last you a good 3 years, give or take! :eek:
Belmont31R
11-02-11, 21:20
Sometimes the military can be slow to change. In pictures I see, though, a lot more military precision guns are using LaRue mounts than used to be the case. Im not sure if LT has been awarded any contracts or they were just COTS purchases. Private purchase a possibility, too. I know I TE'd a LT SPR mount that was designed for a specific scope that didn't have any markings visible and is not commercially available.
Anyways back on track I think the most important thing with the URX is getting the thread locker on the barrel nut and having someone competent install them but even then it happened to me and the person who installed mine would certainly know what they are doing. If one of my factory KAC guns ever loosens up Ill replace it with something else.
Pretty common to use a fired brass case to move the levers on a ARMS mount.
The bottom rail bending thing with the DD RIS-II is news to me. I use mine with a bi-pod, but maybe i'm not leaning enough. ;)
I wonder if that could be a function of the bi-pod which was used as well, or if current production ones had a spec change somewhere.
The screws at the end of the rail are spares, the first screws which hold the rail are maybe 3" back from the front.
After reading Belmont's post, I put my FUG grip as far forward as I could and tried to bend the lower rail down. It didn't budge.
I couldn't be happier with the DD RIS-II. There is a slight couple of ounces you lose to the LITE rail, but having the removable bottom and better profile is worth it to me.
With only the KAC flip-ups, i'm at 7.2lbs. With the Larue FUG, Surefire Scout on its Larue offset mount and rail covers, I'm at 8lbs. When the Schmidt get's here next week i'm guessing its going to be a smidge heavier...
thread locker on the barrel nut
What type are they using?
Belmont31R
11-02-11, 21:24
I think it was at Lightfighter where the guy posted pictures. Can't recall specifics but remember it was from bipod use. I would take it with a grain of salt though since that was a couple years ago and DD may have changed things since then. Maybe there was another contributing factor.
Ive had two DD RIS II's (none at the moment :() and think they are awesome rails.
Robb Jensen
11-02-11, 21:28
I've read some musings that it is fragile. Is it viable for seriously hard combat use?
The U.S.S.S. CAT (United States Secret Service Counter Assault Team) uses them as has/does two other Tier 1 US Gov't units that I know of...possibly even more. Make your own decision. I trust URXII & URXIII rails.
SW-Shooter
11-02-11, 21:45
Can we bring this back on topic, It's unbearable to filter out what is meant for the URX II and the SIR. I could give a squat and crap less about the A.R.M.S. S.I.R.. so please no more about it.
Now How about that URX II Midlength rail system. I have a retailer/installer lined up, I'd like to know if there is a better/stronger alternative that would work under combat conditions, barring intended destruction.
ETA: Thanks Robb, that's the kind of words that give me a warm and fuzzy.
davidjinks
11-02-11, 21:50
I prefer to use link-n-logs...
You should probably write that down.
Don't worry dude, my guess after our conversations is you don't run anything hard, so a Lego hand guard would likely last you a good 3 years, give or take! :eek:
I think KevinB actually had a early URX SR16 or SR15 upper used overseas.
I made a thread on here a month or so ago about my URX II coming loose. I think it may have been from using a receiver block to change out the muzzle device, but I really can't be sure. On my 11.5" upper you can't use a barrel clamp, since the rail covers everything.
The sticking point for me is that you need some very expensive, proprietary tools to install and remove the rail yourself. Not that you should have to do it all that often, I just don't like having to send an upper to a smith just to change a barrel.
That said, I am very happy with my URX, and will probably get an SR-15 upper sometime. I just installed a Troy Alpha rail on my BCM upper, and am very happy with it.
I have never actually seen one in person.
I thought they were the "Elite" rail lol hahaha
Belmont, sorry you got fooled into it. That sucks losing that much money on a garbage product. I would be pretty pissed too.
I know NOTHING about that rail other than I hate the "piggyback" the upper design and its expensive as hell.
Sorry for the hijack there
I've never heard of an ARMS SIR rail breaking, I've got a few that I own, and while they aren't on my duty or training weapons, they still get used on a regular basis.
If someone has first hand experience with one breaking, I would love to hear it. They aren't my favorite rail, but I don't foam at the mouth and throw around internet hearsay about them either. I don't like the cut down the middle of the rail channel, but its not like they are the only company doing it.
The "piggyback" version was an early one, they have had other models out for a few years.
Regarding the original topic, I think a great deal of the URX II and URX III is in the install. The lack of antirotation makes a proper installation the utmost of importance. The stories of these rails coming loose seem to be based around assembly from some place other than the factory.
The URX II upper which I own has never given me trouble, though I'll point out it is a factory assembled unit.
SW-Shooter
11-04-11, 20:52
I'm having Operation Parts do the install. anyone have feedback on them?
ETA: I am purchasing everything from them, so I assume they have history of these installs, so your opinions are valued.
The U.S.S.S. CAT (United States Secret Service Counter Assault Team) uses them as has/does two other Tier 1 US Gov't units that I know of...possibly even more. Make your own decision. I trust URXII & URXIII rails.
Yep. I've seen them on the uppers of arguably the most elite Tier 1 unit in the military so I would say they are durable enough. I have one that's been through the ringer and never had a problem with it. Having said that, they are expensive and I most likely wouldn't own one if I hadn't gotten it so cheap. They are great rails but I think there are other rails just as good for less money.
I was wondering if any of you had any idea where i could purchase extra screws for the URX II. The short ones that need to be removed to detach the lower rail. I used a flat head that was a little thin and notched a screw head pretty good on mine.
-Thanks
justin_247
08-15-12, 10:53
I was wondering if any of you had any idea where i could purchase extra screws for the URX II. The short ones that need to be removed to detach the lower rail. I used a flat head that was a little thin and notched a screw head pretty good on mine.
-Thanks
Call Lawmen's. If they don't know, they can put you into contact with somebody who does.
Certainly haven't used my SR15 in combat conditions, but I have bashed it around pretty good in a variety of classes. I don't baby it and have yet to have any issues. I can see how the front sight might break if you're really abusing it, but I haven't had a problem. YMMV.
Call Lawmen's. If they don't know, they can put you into contact with somebody who does.
thanks
I was wondering if any of you had any idea where i could purchase extra screws for the URX II. The short ones that need to be removed to detach the lower rail. I used a flat head that was a little thin and notched a screw head pretty good on mine.
-Thanks
I don't figure they're using a proprietary screw or anything special. I'd bring it into an ACE Hardware and see if they have the same size there.
sinlessorrow
08-16-12, 16:00
If you like the design of the SIR, VLTOR makes a much better rail system. Similar mounting system but far better. Navy EOD uses them on their MK18's.
That said the KAC rail is on the M110 and seems to be doing well, i still think DD RIS II is a better rail though.
EzGoingKev
08-19-12, 11:45
I was wondering if any of you had any idea where i could purchase extra screws for the URX II. The short ones that need to be removed to detach the lower rail. I used a flat head that was a little thin and notched a screw head pretty good on mine.
-Thanks
I emailed KAC's customer service about buying some spares and they just sent me some for free.
I emailed KAC's customer service about buying some spares and they just sent me some for free.
Not surprised! ;)
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