Rail length questions

[guncoachgt]

First off, Merry Christmas everyone!

Second, as I've said before I'm fairly new to the board and to the AR platform. I'm looking to buy a quad rail for my m&p OR model. My question is what length should I go with for my rail. Carbine, mid-length, forearm? Or is this just a personal
Preference? I know I'll have to install a low profile gas block.

And I'm currently looking at the Yankee Hill Diamond Series rail.

 

[red dragon]

Welcome and Merry Christmas! The m&p 15 OR models all come standard with carbine length gas systems. you can use any carbine length drop-in rail on your rifle without having to change the gas block.

 

[JaPes]

Rail length is up to you. There are pro's and con's to each length. Shorter rail systems are lighter, but offer less rail space & shorter sight radius. Longer rail systems are heavier, but offer more rail space & longer sight radius. Also take into account the way you'll use your rifle, and the way you hold it. Do you prefer to hold your rifle with your off hand on the magwell, a vertical grip on the rail? Do you subscribe to holding the rife with your off hand as far out as possible to facilitate fast lateral transitions? Do you want to hold onto a thick quad rail system? Do you want a forearm where you can mount rail sections where you need them; reducing the weight and diameter of the rail system? Are you going for a particular look?

A couple months back, I made the same evaluation you're going through now. I wanted a 15" length free float rail. I wanted a narrower-diameter rail system. I wanted the option of off hand magwell grip, a VFG, and punching out my grip as far as possible. I also did not want to have to change the standard barrel nut.

A Troy Alpha Rail fit my purpose of use. I pay a weight penalty, but get off hand placement versatility and a longer sight radius. I get a narrower diameter fore end than with a quad rail system.

Merry Christmas!

 

[guncoachgt]

I'm definitely going with a free float rail.

 

[427mach1]

I've got a very nice Yankee Hill Machine free-float quad rail for sale in the accessories section of this forum!

 

[BillyJack2012]

As stated above, it's all personal preference. Here's my 12" on my OR.

 

[guncoachgt]

Billyjack, what low-pro gas block did you go with? I've seen many out there just not sure what I should go with.

 

[BillyJack2012]

There are plenty of good options out there. I got my from Tactical Machining (currently out of stock) as they are a solid local company. Rainier has some for $39. I'll let others chime in with what they have experience with.

 

[ChattanoogaPhil]

If you want to cover a low profile gas block and go with same plane sights.... I went with the YHM specter length 9.6in. It covers the gas block just far enough to where it will accommodate an endcap. I liked the look similar to my 1522.

 

[guncoachgt]

Phil, I'm leaning toward the Spector length right now. What has block did you go with?

 

[kb18no1]

I have a Larue Low Profile Gas Block on my M&P15 OR. They are top quality. I also think they have the best mounting. You will have to dimple barrel and use set screws to mount. LaRue Tactical Low-profile Gas Block LT202 | LaRue Tactical

Or you could go with one that clamps on.


Here is a video to give you an idea how the process works. Removing front sight block, cutting delta ring and installing free float hand guard on AR-15 - YouTube

 

[ChattanoogaPhil]

Phil, I'm leaning toward the Spector length right now. What has block did you go with?

Low Profile Gas Block YHM-9384. It's the one YHM puts on their complete uppers.

 

[dannybot]

If you get anything longer than a carbine length, be certain to chck the weight. This is especially important if you plan on putting any accesories on the rail.

A cheaper rail can add close to a pound to your gun, and it's out front where it's harder to control. Next you throw on a grip @6 oz, light @6 oz, laser @ 6oz, bipod @ 9 oz... You can put two puonds on the front of your gun and can't lift it!

 

[guncoachgt]

Thanks for the advice Dannybot!

I went with the spector length Yankee Hill Diamond Series. It's listed at 15.9oz, every other spector rail that I looked at was 11-12oz. I can sacrifice the 3 or 4oz for the look that I really want.