Rainier Arms 15" Evo Rail Review [Archive]

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BufordTJustice

12-23-13, 15:36

I just received an RA 15" evo rail and wanted to opine about it. I am using this on a new patrol upper I'm building using a BCM blem upper receiver and RA 18" Mountain Series gov-profle barrel with rifle length gas system. Going for a relatively light weight upper that is accurate and shoots SOFT. Going to be used with my gen4 LMT E-carrier and likely a Griffin Armament M4SD II (haven't decided yet on the MD). The profile is just ever-so-slightly larger in diameter than the Troy TRX extreme that my buddy has. I like it. Thumb-over grip is easily acheivable and I have smaller than average bitch-mits for a guy of my height and weight (5'10" and 240lbs).

First, some weights.

15" RA Evo naked (but including the 3 attachment screws): 11.0oz

Each SS barrel bushing: 1.3oz (2.6oz total)

Included anti-rotation QD sling mount w/ backing plate and two YFS screws: .8oz

BCM barrel nut: 1.3oz

Total weight: 15.7oz

I'm impressed at how light it feels. I did a quick mock-up and came to another realization.....that the overall weight is deceptive because the barrel bushings are located directly over the std barrel nut. So, the weight when you shoulder the gun is much more evenly distributed and makes it feel like a lighter rail than the overall weight suggests. The dual anti-rotation tabs fit tightly, but do not gouge, the BCM upper receiver.

When installed properly, the barrel bushings allow an amazingly tight installation. Let's now define "properly". This means that the bushing should be installed with the half-cut-out holes of the bushing facing eachother at the bottom of the barrel nut. Also, you'll notice that the holes that lock onto the lugs of the barrel nut are not equidistant from the edges of the bushing. The holes are closer to one side (I'll call this the "short side"). The short side should be facing away from the upper receiver. This is for good reason. it means that when you follow the REST of the instructions, and you begin tightening the rearmost pinch-screw first, you are actually causing the bushings to flex inward with the handguard and preventing any forward movement of the handguard at all because the rear of the HG is slightly "coned" inward over the part of barrel bushing that is closest to the face of the upper receiver.

This brings me to the coup-de-grace to handguard movement which, as far as I know, has gone previously unadvertised. It's not even in the manual that came with the handguard.

I'll start with pictures.

http://i238.photobucket.com/albums/ff225/deliriou5/20131223_152035.jpg (http://s238.photobucket.com/user/deliriou5/media/20131223_152035.jpg.html)

You'll notice that the bottom of the " bulge" has been tapped for a screw which would serve to press against the barrel bushing even more and prevent forward slippage. I really like this type of value-add. RA and Samson didn't call attention to it and RA didn't charge any more for it. Excellent. Now for the cherry on top...

http://i238.photobucket.com/albums/ff225/deliriou5/20131223_152147.jpg (http://s238.photobucket.com/user/deliriou5/media/20131223_152147.jpg.html)

Depending on what happened to the photo during upload, you'll see that the set screw is not the only bonus...but it also has a KNURLED CUP TIP. YEAH BABY! That's what I'm talkin 'bout!

Didn't charge a penny more and that substantially enhances the design's only theoretical weak point. Even though, I can assure you that the rail would not be shifting in any direction if you properly install the barrel bushings and tighten the two HG pinch screws in the proper order (beginning with the screw closest to the upper receiver face). I was unable to get the rail to shift forward even when I used Slip2000 EWL between the bushing and the rail and didn't use the added set screw on the bottom. I tried to 'hercules' it apart and was unable to get it to move at all. Even after repeated 'isometric activities'. I'm satisfied. I've since degreased everything in prep for final installation.

Overall, I'm very happy. A 15" rail that is sturdy, light, and under two C-notes shipped to my door.

Steel head

12-23-13, 18:51

I've got the 12" version on my AR.
I really like it.
Quite comfortable in hand and the price is decent.
I think they look better than the regular Samson EVO.

quaesitor logica

12-23-13, 22:59

Are the rails exactly the length advertised or are they a bit longer than the specified length? I have a 12" upper I would like an 11" rail riding.

BufordTJustice

12-24-13, 01:09

Mine is exactly 15.0", not counting the anti-rotation tabs.

eperk

12-24-13, 06:11

titanse05

12-24-13, 07:30

I bought one this time last year. I love it and also have the 15". The weirdest thing is that mine doesn't have the set screw or even the threaded hole for it. They must have tweaked the design since I purchased mine.Yeah that had to be a recent tweak. My 12" version lacks the extra set screw but I have had no issues with movement or flex in the almost two years I've had it. Great handguard.

BufordTJustice

12-24-13, 09:20

I bought one this time last year. I love it and also have the 15". The weirdest thing is that mine doesn't have the set screw or even the threaded hole for it. They must have tweaked the design since I purchased mine.

Seeing the way the clamp works over the barrel bushing, I would be perfectly happy with it if it did not have the additional set screw. It's on there as long as you don't install the bushing backwards. Still, I like seeing this type of innovation.

I know I've seen the regular Samson Evo (non RA version) on dozens of guns at the 3-gun matches I've attended. So, it may not be Larue-tough (hell, it might be, I dunno), but it doesn't have any obvious weaknesses when you consider it's design and intent (it's light, it's sturdy, and it's strong).

I was thinking about the Centurion CMR before pulling the trigger on this. I have not doubt that the Centurion is a better made rail. But, it also costs another C-note. To me, I don't get anything additional for that extra money aside from a slightly smaller outer diameter, included QD studs, and some really slick accessories. That wasn't enough for me to spend an additional $100 over the RA evo. For somebody else who is in a different boat, it might be. Who knows.

Also, the weight of the CMR and the RA Evo appear to be relatively similar from the info I've gathered on the interwebz (CMR 14" is somewhere above 14oz as far as I can gather....so about an ounce lighter).

Is the RA Evo the best HG for everybody? Nope. That's an impossible statement. But it's one of the good ones from what I can tell. I'll keep this thread updated as I get this rifle qual'd and bring it on patrol. Having it banging around in my patrol car's trunk and rifle rack (and deploying it for Gawd-knows-what) will certainly reveal any weaknesses. I'll advise once I get to that.

Next step, more pix and some shooting impressions of the overall upper once I get it properly assembled. I'm waiting on the Brownells upper lapping tool (http://www.brownells.com/gunsmith-tools-supplies/rifle-tools/receiver-tools/ar-15-m16-upper-receiver-lapping-tool-prod20220.aspx?psize=96) before I install the barrel on the upper for good. I love Brownells. :D

Steel head

12-24-13, 13:28

I bought one this time last year. I love it and also have the 15". The weirdest thing is that mine doesn't have the set screw or even the threaded hole for it. They must have tweaked the design since I purchased mine.

I emailed them about it as it was not mentioned in the directions.
They said it was added pretty recently mainly for heavier recoiling rifles.

BufordTJustice

12-24-13, 13:38

I emailed them about it as it was not mentioned in the directions.
They said it was added pretty recently mainly for heavier recoiling rifles.

Makes sense to me as it seems it would be superfluous for 5.56. Maybe on a 6.8/6.5/.450 bushmaster/.50 beowulf setup. But the added insurance for no extra cost is nice.

I would sleep soundly even if the rail didn't have it.

DM-SC

12-24-13, 14:14

I have to agree that the Evo rails are great. I have the RA version on a 6920 and the Samson version on a PSA.

quaesitor logica

12-24-13, 21:49

Thankyou for the informative review. Looks like a solid good looking rail. An 11" looks great for my shortie

RogerinTPA

12-24-13, 23:19

Post some pics when you get it put together;)

MudPhud

12-25-13, 09:26

At the risk of igniting anti-piston sentiments, I'll just say that I'm extremely glad that Samson has been offering this piston-compatible Evolution handguard for a while now. They are certainly one of the first to introduce a lightweight, slick rail that can accommodate several piston systems. I happen to like the Rainier Arms version better:

22277

While I have other rails by Centurion Arms (C4 and CMR), Daniel Defense (RIS II), Fortis (REV), Geissele (SMR MK3), Knight's Armament (URX 3), Lancer Systems (LCH5 carbon-fiber), Noveske (NSR), Troy (TRX Extreme), and VLTOR (CASV-ELS) on other traditional AR-15s, Samson/Rainier is the only one I have for my LWRCI rifles. Thumbs up for all American innovators.

BufordTJustice

12-25-13, 11:23

Post some pics when you get it put together;)

Will do. And Merry Christmas, btw. :)

Sent from my SPH-D710 using Tapatalk

03scgt

12-26-13, 20:24

I wish they made these in 10",I'm doing a 10.5 and fear even with a surfire or similar brake the 11" would be too long

din

12-27-13, 04:01

I wish they made these in 10",I'm doing a 10.5 and fear even with a surfire or similar brake the 11" would be too long

They do, just not the Rainier version. Go poke around the Samson website, find a length you like and do some comparison shopping. I managed to pick up an 11" to replace my 7-EX for around $140 shipped.

TF82

12-29-13, 00:30

Nightvisionary

12-29-13, 07:42

This is a timely post. I'm about to buy a free float tube and have pretty well narrowed it down to this or the Midwest Industries Gen 2 SS. I'm not in a position to handle either, but this system just seems to be a bit more solid overall to me. Did you have any issues with it canting up or down as you tightened it? Also, has anyone tried the Samson Evo Shields yet?

I have two Rainier/Samson Evolutions and one MI Gen 2 SS. Both are great. The MI is perhaps the lightest and slimmest rail available. The Evolution has a better mounting system and feel a little more solid. I like both but if I had to choose one it would be the Evolution.

eperk

12-29-13, 07:59

I have both also. The MI is on my LMT 16" carbine. I love that rail. The Evolution in on my 18" middy that I use for longer range shooting. I love that rail also. Like others have said, you can't go wrong with the Samson.

DMViergever

12-29-13, 10:20

I had two of the original Samsons and one was actually a prototype but I had to tighten them up from time to time so the added screw ia a nice touch!

BufordTJustice

12-29-13, 11:20

I had two of the original Samsons and one was actually a prototype but I had to tighten them up from time to time so the added screw ia a nice touch!

Yeah, for small screws, I don't actually use blue loctite anymore. I use Blue Vibra-tite Gel. It stays put and seems to resist vibration better than normal loctite. I have used it on scope rings for many a precision rifle. It is also aluminum friendly.

http://www.brownells.com/gunsmith-tools-supplies/general-gunsmith-tools/thread-locking-liquids/threadlockers-prod42461.aspx

The manual for the rail rec's blue threadlocker...so it'll get a nice dab of VT Blue gel before assembly.

BufordTJustice

12-29-13, 15:02

discreet

01-01-14, 14:58

More pix. Waiting on the V7 lightweight ejection port cover and the PA AFAB to arrive before final assembly.

http://i238.photobucket.com/albums/ff225/deliriou5/DSC02025.jpg (http://s238.photobucket.com/user/deliriou5/media/DSC02025.jpg.html)

http://i238.photobucket.com/albums/ff225/deliriou5/DSC02024.jpg (http://s238.photobucket.com/user/deliriou5/media/DSC02024.jpg.html)

http://i238.photobucket.com/albums/ff225/deliriou5/DSC02023.jpg (http://s238.photobucket.com/user/deliriou5/media/DSC02023.jpg.html)

Looks good an. Def like the Rainier version more than the normal Samson evo. Either way however I don't think I'll be going the samson route again. Just not digging the rail too much nor the mounting system used. Prefer the Centurion or Fortis mounting method much more.

Looking forward to pics to see how the Rainier version looks however.

DMViergever

01-01-14, 15:28

I wonder if the set screw is to help keep the handguard level? I just remembered several folks had problems with these tilting and being uneven when mounting.

BufordTJustice

01-01-14, 18:05

I wonder if the set screw is to help keep the handguard level? I just remembered several folks had problems with these tilting and being uneven when mounting.

It doesn't appear to be. The screw didn't affect the orientation or alignment of the HG one bit when I tightened it.

BufordTJustice

01-01-14, 18:08

The white residue is just dry skin from my hands. Wiped right off after I took the pix.

I'm very pleased so far.

http://i238.photobucket.com/albums/ff225/deliriou5/DSC02037.jpg (http://s238.photobucket.com/user/deliriou5/media/DSC02037.jpg.html)

http://i238.photobucket.com/albums/ff225/deliriou5/DSC02035.jpg (http://s238.photobucket.com/user/deliriou5/media/DSC02035.jpg.html)

http://i238.photobucket.com/albums/ff225/deliriou5/DSC02034.jpg (http://s238.photobucket.com/user/deliriou5/media/DSC02034.jpg.html)

http://i238.photobucket.com/albums/ff225/deliriou5/DSC02033.jpg (http://s238.photobucket.com/user/deliriou5/media/DSC02033.jpg.html)

http://i238.photobucket.com/albums/ff225/deliriou5/DSC02032.jpg (http://s238.photobucket.com/user/deliriou5/media/DSC02032.jpg.html)

http://i238.photobucket.com/albums/ff225/deliriou5/DSC02031.jpg (http://s238.photobucket.com/user/deliriou5/media/DSC02031.jpg.html)

http://i238.photobucket.com/albums/ff225/deliriou5/DSC02029.jpg (http://s238.photobucket.com/user/deliriou5/media/DSC02029.jpg.html)

http://i238.photobucket.com/albums/ff225/deliriou5/DSC02028.jpg (http://s238.photobucket.com/user/deliriou5/media/DSC02028.jpg.html)

http://i238.photobucket.com/albums/ff225/deliriou5/DSC02027.jpg (http://s238.photobucket.com/user/deliriou5/media/DSC02027.jpg.html)

mpom

01-01-14, 20:14

BufordTJustice

01-01-14, 20:49

Noticed there is a slight gap between HG and upper receiver; is that intentional?
Also, how do you know when to stop tightening the 2 bolts clamping the rear of the HG? On my 12" Evo I ended up tightening till the gap disappeared. No play even without the new set screw.
Very happy with it.

Well, that is just the way it lined-up after tightening. You can't even fit a post-it note in there (I just tried) and it is laterally uniform. I've seen several big-name rails with visually larger gaps than that (but they were still rock solid). I'm not sweating it.

As for tightening, I don't have a wheeler FAT wrench. I'm a pretty strong guy, so I just tighten until I start to feel reasonable resistance. I purposefully have a set of cheap hex wrenches that bend easily for jobs like this ($1.99 for a 12 pack at Harbor Freight). Once the wrench starts to flex, I stop.

The right way to do it is to know how many inch-lbs you are putting on the fastener via the FAT wrench. Also, no torque spec was called-for in the installation sheet.

mpom

01-02-14, 09:31

Thanks!
Looking forward to your review of the newer muzzle device in another thread. Ran a BC then the Griffin Flash Comp, now the Dynamic Resistance Comp.

BufordTJustice

01-15-14, 17:52

Alright. Still digging this rail. Lightest 18" upper i have yet held or shot. Only way to go lighter is the BCM kmr 15" which doesn't even exist yet.

Gun with aimpoint t1 in a Larue lt660, Magpul mbus front and rear, BCM gunfighter mod 4, umbrella corp grip, Magpul aluminum trigger guard, bad lever, precision armament AFAB, 4140 steel gas block, Rainer sling mount, 15" Evo rail, Vltor A5 receiver extension with a5h3 buffer, Magpul STR with enhanced buttpad, single cr123a battery, and a small bottle of machine gunners lube.

All of that weighs 7.71 lbs. F@CK YESSSSSSSS!!!!!!!!

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BufordTJustice

01-15-14, 18:01

Also thinking about a titanium forward assist....

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BufordTJustice

03-03-14, 11:30

Alright, I just uninstalled this rail in anticipation of my 13.5" KMR arriving tomorrow and DAMN was it difficult to get off (but in a good way).

Lockup is ROCK solid. It was so solid, I had to put my upper in a vice to get the rail to slide off AFTER I removed all the clamping screws and dripped some FireClean lube in between the heat sinks and the rail (and twisted/pulled a LOT before putting it in the vice). I'm a big guy and it took quite a bit of pulling on my part even when using the vice, despite the fact that rail still had some residue of lube in between the heat sink pieces and the rail where the fireclean had not yet migrated to (it was not dry).

To achieve this level of strength on the install, just tighten the clamp screws until the sides of the clamp are touching or nearly touching with some blue loctite on the threads. Let the loctite set for at least 24 hours before shooting it and you're golden.

Despite the fact that I'm transitioning to the KMR, I am very pleased with the rail, and even more so after uninstalling it, as I know there were doubts or questions about the strength of the lockup. Bottom line: fear not, this bitch is ON THERE if you tighten the screws properly and use blue loctite or equivalent. That is all.