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View Full Version : I think I want to try a drop-in carbine rail...



HeavyDuty
04-30-10, 22:37
I've generally been happy with the MOE handguard on my carbine, but I'm tempted to try a drop-in quadrail to make it easier to mount a light, VFG and sling point. I do not want a FF rail on this one; if I did, I'd go with an Omega and be done with it.

I'd like to find one that's slimmer than it is tall. Suggestions on what ones to consider? It's hard to tell the cross-section of most rails from the photos I can find. Most of the compilation threads I've found have been for freefloats.

The only one I've found so far that definitely is narrow is the Ergo Z Rail drop-in. There have to be others, right?

Quib
04-30-10, 22:59
Take a look at the RAS seconds offered by KAC.


http://farm5.static.flickr.com/4055/4546295701_a722e5af06_o.png


http://www.knightarmco.com/shop/index.php?main_page=product_info&cPath=2&products_id=32

glocktogo
04-30-10, 23:11
Any particular reason you don't want a free float? Because the Omega is a drop in and it fits all your other criteria perfectly. It's also one of the lightest available, which is a huge plus.

If you don't want an Omega, why not just get the new MOE 4 piece light mounting kit and the new MVG foregrip designed for the MOE HG's? Add a Daniel Defense QD sling point and you're set for a lot less $$$ than a new rail! :)

HeavyDuty
04-30-10, 23:52
Take a look at the RAS seconds offered by KAC.

Is the KAC RAS oval? I thought they were round.


Any particular reason you don't want a free float? Because the Omega is a drop in and it fits all your other criteria perfectly. It's also one of the lightest available, which is a huge plus.

If you don't want an Omega, why not just get the new MOE 4 piece light mounting kit and the new MVG foregrip designed for the MOE HG's? Add a Daniel Defense QD sling point and you're set for a lot less $$$ than a new rail! :)

Omega is a little pricey for me right now but I might still end up with one.

That's basically what I'm doing with the MOE (with an HK hook loop instead of a QD and a custom stubby VFG used as a handstop instead of a MVG), I just want to consider alternatives.

I like the MOE, but I keep coming back to the feel of my A2 corncobs - so I wonder if I should try a rail.

bobvila
05-01-10, 00:28
DD EZ rail?

It isnt FF and is alot cheaper than the omega rail, but looks like it is the same shape.

OPPFOR
05-01-10, 00:29
Have you seen this yet? A little cheaper than the omega.

http://www.bravocompanyusa.com/Daniel-Defense-EZ-CAR-7-0-Rail-Carbine-Handguard-p/dd%205010.htm

Quiet-Matt
05-01-10, 07:18
The Troy DI is a little narrower that it is tall. Sucker locks up tight as well. I went with it over the KAC because the Troy has swivel sockets front and rear on both sides.

kry226
05-01-10, 07:30
So what's the real-world difference between the DD Omega and the EZ?

bobvila
05-01-10, 07:41
It is not a free float rail, and it doesnt have QD sockets.

HeavyDuty
05-01-10, 07:47
The DD EZ was one of the first ones I considered, but I've heard from a few places that they're not oval or are just barely. Does anyone here have one that can comment?

QD sockets are not a selling point for me - I use HK and MASH hooks.

PRTrooper
05-01-10, 07:49
I've got two Troy MRF-DI (M4) and they are rock-solid. Can't beat it for the money, and the QD sockets are perfect. Highly recommended!:D

HeavyDuty
05-01-10, 07:53
I've got two Troy MRF-DI (M4) and they are rock-solid. Can't beat it for the money, and the QD sockets are perfect. Highly recommended!:D

Do you have a way of measuring the height and the width of the MRF-DI?

Cowtown556
05-01-10, 08:28
I got the Troy, it will not move at all.

austinN4
05-01-10, 08:45
DD EZ rail? It isnt FF and is alot cheaper than the omega rail, but looks like it is the same shape.
Yup, this is what I was going to suggest.

HeavyDuty
05-01-10, 08:49
Per a post from Joe Marler at TOS the DD EZ is 2.4" wide - plumper than I would care to try.

Karcas
05-01-10, 08:58
No idea on dimentions but here is a shot of a Troy MRF-DI

http://i49.photobucket.com/albums/f283/mayhem90gsx/Troy20MRF20DI209-4.jpg

Quib
05-01-10, 10:35
Is the KAC RAS oval? I thought they were round.

How pronounced of an oval shape are you looking for? Drop in rail widths are pretty limited I believe, compared to FF rails.

The height of any rail will be locked in at the height of the upper receiver. This only leaves room for variations in the width of the side rails and lower rail. With drop-in rails, width wise, you really cant get any thinner than the diameter of the D-ring. There's a little working room there for variation.

This leaves the lower rail and how far it can hang down.

The KAC RAS I have measures 2.29” high, rail outer surface to outer surface. Width comes in at 2.18”, rail outer surface to outer surface.

For quality verses price, I think these RAS Seconds are a hard deal to beat, and they would be my recommendation. I’m glad I was alerted to them when I was shopping for a new, better quality rail system.

Kilo 1-1
05-01-10, 10:55
I'm with Quib on getting a KAC RAS at that price point. I got mine new for $145 a few years back.

HeavyDuty
05-01-10, 23:04
No idea on dimentions but here is a shot of a Troy MRF-DI

http://i49.photobucket.com/albums/f283/mayhem90gsx/Troy20MRF20DI209-4.jpg

Clearly oval! Thanks for the pic - I'll keep looking for the width.


How pronounced of an oval shape are you looking for? Drop in rail widths are pretty limited I believe, compared to FF rails.

I'd like to get as close to (or under) 2" width as possible.

justin_247
05-02-10, 03:13
Clearly oval! Thanks for the pic - I'll keep looking for the width.

I'd like to get as close to (or under) 2" width as possible.

I think your best bet is going to be the Ergo Z Rail. Unfortunately, I couldn't find the dimensions for it, but if you look at this thread (http://www.weaponevolution.com/forum/showthread.php?1227-ERGO-Z-Rail-Two-Piece-Replacement-Handguard-Rail-System) over at Weapon Evolution, you can see it has a very, very oval profile, much more so than any of the other systems (except for the DD Omega, which I still think you should strongly consider). According to this thread (https://www.m4carbine.net/showthread.php?p=568322), the Ergo rail has the same dimensions as the Omega.

Here's some info I gathered on the net about the widths of other rails to help you decide:

DD Omega - 1.9"
VLTOR CASV-M - 2.12"
KAC RAS - 2.18"
MI MCTAR 17 - 2.45"
Troy MRF-DI - ?
Doublestar 2-piece Tactical Handguards - ?
Samson STAR-DI - ?

rychencop
05-02-10, 05:26
get the RAS or DD's new drop in.

HeavyDuty
05-02-10, 09:25
I think your best bet is going to be the Ergo Z Rail. Unfortunately, I couldn't find the dimensions for it, but if you look at this thread (http://www.weaponevolution.com/forum/showthread.php?1227-ERGO-Z-Rail-Two-Piece-Replacement-Handguard-Rail-System) over at Weapon Evolution, you can see it has a very, very oval profile, much more so than any of the other systems (except for the DD Omega, which I still think you should strongly consider). According to this thread (https://www.m4carbine.net/showthread.php?p=568322), the Ergo rail has the same dimensions as the Omega.

Here's some info I gathered on the net about the widths of other rails to help you decide:

DD Omega - 1.9"
VLTOR CASV-M - 2.12"
KAC RAS - 2.18"
MI MCTAR 17 - 2.45"
Troy MRF-DI - ?
Doublestar 2-piece Tactical Handguards - ?
Samson STAR-DI - ?

Thank you! Your search-fu is more powerful than mine, plus the hospital blocks most weapon sites when I try and research.

I've been slowly coming to the same conclusion, that the Ergo may be the one to try. If I find I really like the concept (not a sure thing at this point) I can always bump the Ergo down to the .22 and get a Omega for the 5.56.

Thanks again!

HeavyDuty
05-02-10, 14:18
Fuggit - it's only money, so I ordered an Ergo Z Rail two piece from my usual pusher. You can tell it's narrow by looking at how the Delta ring and front HG cap are almost flush with the side rails (this is zero7one's pic over at WE, so I'll just link it): http://i726.photobucket.com/albums/ww265/zero7one/2009_05_16_0072.jpg

I'll give it a try with both rail covers and ladders, plus the new RVG I picked up for the 9mm and my TLR-1. If I decide I don't like having a quad on this carbine I won't take much of a loss selling it; if I decide I like it I'll bump the Ergo down to my .22LR AR and order an Omega for the 5.56.

Quib
05-02-10, 19:48
Let us know what you think of the Ergo. :)

Ruff Shod
05-02-10, 20:31
Have you looked at MI?

http://www.midwestindustriesinc.com/index.cfm?fuseaction=category.display&category_id=64

HeavyDuty
05-02-10, 21:34
Have you looked at MI?

http://www.midwestindustriesinc.com/index.cfm?fuseaction=category.display&category_id=64

At 2.45" wide, zero interest.

HeavyDuty
05-02-10, 21:35
Let us know what you think of the Ergo. :)

Will do! It'll be a limited comparison against my existing MOE HG and an A2 corncob. It wouldn't really be comparable to a free float rail.

HeavyDuty
05-06-10, 20:56
Let us know what you think of the Ergo. :)

OK, the Ergo arrived today. First thoughts:


It mounted up extremely easily, to the point that I was worried it would be loose. Not an issue, it's solid after you install the four screws.

The size is close to perfect for me. The width over the flats is 1.89" (48mm); the height is 2.44" (62mm). I'm certain I wouldn't have been happy with a wider rail like the DD EZ or the MI.

As I feared, a carbine rail really isn't long enough for effective 3:00 mounting of a TLR-1. I'm thinking about picking up a cantilever mount like the DD and mounting it either as far forward as possible on the side or to the top rail hanging out at about 1:30.

Fit and finish is very good.

I've been playing around with my motley collection of rail covers - XTs, XTMs and ladders - and think I like the XTMs the best. The rail is narrow enough that the front end side XTMs need to have their backside slightly clipped to avoid interfering with the handguard cap - no big deal, not even visible. The backside of XTs just clear the handguard cap.


I'll try and get some pics up in the next few days. So far so good.

One thing that really surprised me - the new Magpul RVG isn't one XTM segment long. I thought that would have been a no-brainer.

HeavyDuty
05-09-10, 07:23
I pulled it this morning so I could Loctite the mounting screws and get a weight - 10.6 oz with screws. Lighter than I expected.

justin_247
05-09-10, 07:38
Sounds like it's exactly what you were looking for, so far. Is it pretty rock solid?

Be sure to post a pic when you're done.

HeavyDuty
05-09-10, 08:18
I'm just waiting for a full set of rail covers to be delivered - it's a bit of a mutt at the moment.

I'm *very* impressed with how solid it locks up. I have a VFG on it right now and I can't get the rail to budge.

rob_s
05-09-10, 08:40
Maybe I missed it, but any particular reason you're not going FF? Is it strictly a cost issue?

Also, FWIW, I find carbine-length rail systems to be a total waste whether FF or not. They are too short for me when using them for what they are intended (as attachment points for other equipment) beyond maybe a vertical foregrip and even then I want to place it far enough forward that I wind up grabbing the FSB.

YMMV

HeavyDuty
05-09-10, 09:15
Maybe I missed it, but any particular reason you're not going FF? Is it strictly a cost issue?

Also, FWIW, I find carbine-length rail systems to be a total waste whether FF or not. They are too short for me when using them for what they are intended (as attachment points for other equipment) beyond maybe a vertical foregrip and even then I want to place it far enough forward that I wind up grabbing the FSB.

YMMV

Yep, this was pretty much a cost control - I wasn't sure if I'd like carbine-length rails, but I wanted to experiment with better VFG, sling point and light mounting than I was getting with my MOE handguard without spending Omega kind of money.

I'll run this Ergo for a few months to test the concept and then either go back to the MOE or upgrade to a DD Omega. If I decide to go with the Omega, the Ergo will probably get kicked down to the .22LR or sold off.

justin_247
05-09-10, 09:15
Maybe I missed it, but any particular reason you're not going FF? Is it strictly a cost issue?

Also, FWIW, I find carbine-length rail systems to be a total waste whether FF or not. They are too short for me when using them for what they are intended (as attachment points for other equipment) beyond maybe a vertical foregrip and even then I want to place it far enough forward that I wind up grabbing the FSB.

YMMV

My AR I use primarily for training purposes since we use M-4s, but don't get much time on the range with them. We use the KAC RAS carbine-length rail systems and haven't transitioned to longer ones in the service, so I train with the closest I can get to what I'm issued. In fact, I haven't even kept my RAS on my carbine at home and instead shoot with the stock handguards.

Given a choice, I'd much prefer a midlength system, but the military doesn't seem much interested in going to that kind of system anytime soon. If they do, it'll be the result of a caliber change to 6.5 or 6.8 where they'd end up re-barreling the existing receivers, however I don't see this as very likely in the immediate future, especially since they seem interested in procuring a whole new weapons system instead of merely upgrading the M-4 beyond a few components (heavier barrels, for example).

On another note, in case anybody cares, DD Omega X FSP 12.0s are on sale at BCM right now for $179.

RogerinTPA
05-09-10, 09:39
I would have went with the DD Omega-X 12.0 FSP, since I like to get my hand farther out on the rail and they have a smoking deal on these, Just $179.00 at Bravocompanyusa.com. http://www.bravocompanyusa.com/Daniel-Defense-OMEGA-12-0-FSP-Rail-p/dd%2010005.htm

HeavyDuty
05-09-10, 09:43
I would have went with the DD Omega-X 12.0 FSP, since I like to get my hand farther out on the rail and they have a smoking deal on these, Just $179.00 at Bravocompanyusa.com. http://www.bravocompanyusa.com/Daniel-Defense-OMEGA-12-0-FSP-Rail-p/dd%2010005.htm

Nice rail, but not an option for this 14.5" build:


Utilizing a proprietary barrel nut...

Quiet-Matt
05-09-10, 10:27
And by using a carbine rail on your 14.5", you can use your bayonette.;) Seriously though, I have a 12" rail on one gun and this on my beater. I find that even on the 12" I tend to only use the same area as the carbine rail. I guess it's the way I'm built, but both work equally well for me. And hey, I can use my old bayonette if the need ever comes up.:D
http://lh3.ggpht.com/_5kA3JwNkBxc/S-bRhqem2ZI/AAAAAAAAF74/9gkqs7MIIY8/s720/mms_picture.jpg

rob_s
05-09-10, 10:40
Yep, this was pretty much a cost control - I wasn't sure if I'd like carbine-length rails, but I wanted to experiment with better VFG, sling point and light mounting than I was getting with my MOE handguard without spending Omega kind of money.

I'll run this Ergo for a few months to test the concept and then either go back to the MOE or upgrade to a DD Omega. If I decide to go with the Omega, the Ergo will probably get kicked down to the .22LR or sold off.

Proof of concept. Make sense.

I do the same thing a lot. I have primary guns that are set up in ways that I know for a fact work for me and my purposes, and then I have test-bed guns that I mess around with and try new things. Sometimes the test-bed gun gets so good it changes roles and becomes the primary! That's actually how I wound up back at no-VFG MOE forend for my primary and am chomping at the bit for the mid-length MOE to be released for it's 16" sister

HeavyDuty
05-09-10, 10:57
What can I say - I've been burned enough times by my assumptions that I always want to test new concepts before I jump.

I are an analyst.

HeavyDuty
05-11-10, 08:10
Still thinking about the front sling point - I'm leaning to a Gear Sector HK hook plate at the left rearmost position. So far:

http://i892.photobucket.com/albums/ac123/HDF62/AGP-1-1.jpg

Notice the oval shape, similar to a DD Omega:

http://i892.photobucket.com/albums/ac123/HDF62/DD-Light-Mount.jpg

sdcromer
05-11-10, 19:12
Now we just need an Ergo for the mid lengths. Great review! :D

Jimbo45
05-12-10, 02:38
Now we just need an Ergo for the mid lengths. :D

This +1

LAWMAN34
05-12-10, 17:52
MI or TROY drop in can't go wrong with either

HeavyDuty
05-12-10, 22:49
MI or TROY drop in can't go wrong with either

Don't take this wrong, but... did you read the thread at all?

LAWMAN34
05-12-10, 22:56
Thanks for pointing that out. I had multiple windows open and I thought I was responding to another thread..

HeavyDuty
05-12-10, 23:02
Thanks for pointing that out. I had multiple windows open and I thought I was responding to another thread..

I hate when that happens... ;)

tobasco
05-12-10, 23:05
ive got the kac ras on my mk18 clone and love it.

http://i39.tinypic.com/34rx9fn.jpg

variablebinary
05-12-10, 23:17
KAC

http://home.comcast.net/~firearmspics/Colt692011b.jpg

CAVDOC
05-13-10, 09:32
definitely like the KAC- maybe from 2 combat tours with it- but they are available inexpensive usually and not too heavy. I go counter to the current trend of putting my vfg far out on the rail- keeping it just a couple inches in front of the magwell. Again a throw back to mil ops- when you carry the rifle for hours or are standing on the road waiting for eod holding the rifle at some approximation of low ready for long periods of time- just more comfortable for me that way. also never felt there wasn't enough space to comfortable mount and use flashlight etc.

HeavyDuty
06-06-10, 22:04
Update:

The proof of concept worked out well; I'm OK with a carbine length rail. I just committed to a used Omega from a fellow M4C member and will probably be kicking the Ergo down to my .22.