Help with new rail decision!

[Rogue556]

Needing some help guys. I have a Colt 6920 that currently sports a KAC RAS carbine rail system. The rail itself is ok for what it is. It's sturdy, and does what it is supposed to. My problem is I have fairly long arms, and this rail system limits me on how I can control the rifle.

I'm looking for options on a 12" (or more) rail that will do what I need it to. I'm not so much worried about weight as much as how sturdy the system is. Obviously needs to be free float as it's going on a carbine length gas system.

The two I'm debating with right now are the Daniel Defense RIS II M4a1 and the Daniel Defense RIS II M4a1 FSP version. I like the idea of keeping the FSP as it's sturdy when compared to its flip up counter parts. Problem with that version is my current carbine is the only one I own, and keeping the FSP limits me on what optics I can run if I decide to change later (I'm currently running an Aimpoint Comp M2 but have considered something with magnification). So with that being said, for those of you that have used both, what do you prefer and why? I also know there are other offerings out now that could be thrown in with the two mentioned (Troy, KAC, Geissele, etc) , but I wasn't sure if their mounting options were as sturdy and at this point that's most important. What are you all's thoughts? Any and all help is appreciated!

[SpankMonkey]

RIS II M4a1 FSP is rock solid. The only thing you see with a scope would be a slight shadow in the lower third of the glass. You will get used to it real fast and it should not bother you.

[Guinnessman]

Take a look at the Centurion Arms FSP rail. It is easy to install and a great piece of kit.

[Roklok]

Take a look at the Centurion Arms FSP rail. It is easy to install and a great piece of kit.

Ditto!

[LittleBallOfHate]

RIS II M4a1 FSP is rock solid. The only thing you see with a scope would be a slight shadow in the lower third of the glass. You will get used to it real fast and it should not bother you.

+1 On the RIS II. It's my rail of choice.

[Col_Crocs]

Of the others you touched on, check out the Geiselle's mounting design. That's about as sturdy as it gets IMHO. The RISII is great though. My current favorite but the C4 is pretty sturdy too. What I'm trying to get at is, it really depends how much work you're willing to put in.
1. No shave + no disassembly + some cutting = C4 FSP
2. Full disassembly(barrel and FSB OFF) + plus removal of delta ring and HG cap = RISII FSP
3. Full disassembly(barrel and FSB OFF) + plus removal of delta ring and HG cap + FSB shave down = RISII or Geiselle

[wakebrdr142]

+1 On the RIS II. It's my rail of choice.

+2, that's if you can find one.

[LittleBallOfHate]

+2, that's if you can find one.

Rainier has 'em in black currently.

[Frens]

+1 on the Centurion C4,
rock solid and super easy to install

[markm]

+1 On the RIS II. It's my rail of choice.

RIS II is the way to go if you hate the I BEAM feel of the other DD rails and the Centurian.

I'd run strictly Centurian rails if the bottom rail was low profile.