Where does the URX 1/2/3 and URX 4 stand in the rail "hierarchy"?

[pointblank4445]

I've followed both:
https://www.m4carbine.net/showthread...ject-to-moving
https://www.m4carbine.net/showthread...ighlight=rigid

What I would like to know I how the URX's fit into the equation and if their mounting style is a blessing or a curse for keeping and maintaining a rigid and aligned platform for forward mounted laser aiming devices under hard-use conditions.

Furthermore, is the one piece design of the #4 series an improvement in this respect over the earlier URX? And how might this change if the URX1/2/3/3/1 is properly milled/timed (per the Marvin Pitts method) to be aligned to the upper AND secured with separate barrel nut?

[Mr. Goodtimes]

I have an SR-15 MOD 2, so it has the URX4 on it. In my opinion the integrated barrel nut is pretty slick. If the rail comes lose, that means whatever produced that sort of force produced enough torque to unscrew the barrel but as well, so at that point you have bigger fish to fry than you're rail being lose or your laser device / iron sights losing zero.

I think the whole thing gets overplayed too. I've been into AR's seriously for about ten years now and I don't know anyone (including my self) who has had a rail from a reputable manufacturer come lose. You would have to create some SERIOUS mechanical forces to break loose a KAC, DD, Larue, Centurion, Geissele etc... rail.

Buy a rail from a reputable manufacturer and shoot more and worry less.


Sent from my iPhone using Tapatalk

[pointblank4445]

I have an SR-15 MOD 2, so it has the URX4 on it. In my opinion the integrated barrel nut is pretty slick. If the rail comes lose, that means whatever produced that sort of force produced enough torque to unscrew the barrel but as well, so at that point you have bigger fish to fry than you're rail being lose or your laser device / iron sights losing zero.

I think the whole thing gets overplayed too. I've been into AR's seriously for about ten years now and I don't know anyone (including my self) who has had a rail from a reputable manufacturer come lose. You would have to create some SERIOUS mechanical forces to break loose a KAC, DD, Larue, Centurion, Geissele etc... rail.

Buy a rail from a reputable manufacturer and shoot more and worry less.


Sent from my iPhone using Tapatalk

Been there, done that, got the T-shirt. To date, I've had:
12+x KAC rails
9x DD
4x Geissele
2x Larue
2x Centurion
1x BCM KMR
10+ other rails (HK, PRI, etc.)

For the casual user, I agree the whole thing gets overplayed on the commercial end. However, a vast majority of my builds for myself and were with precision in mind. When you get down to it and start applying pressure on rails via bipods and barriers things can get interesting in terms of performance. There is also the issue in the trend with longer, thinner rails and dealing with their added susceptibility to flex more with less force applied.

I have also had more than a few rails take a knock and have the "monolithic" rail become misaligned from the receiver.

They ALL have their pro's and con's, you just have to pick your poison. I have yet to come across anything that didn't have at least one huge design flaw to it.

I appreciate the response, but I'm not "looking to buy." I legitimately what to know the technical merit of the design(s) in question...IF anyone is able to do so.

[scottryan]

URX rails do not need to be milled and timed.

It pisses me off when people do this. This is a cosmetic issue only and gains you nothing except removing the protective anodizing from the back of the rail.

Install it the factory way.