[blackguns3000]

I have an m4, which has the ~~7" plastic hand guard. I know I can get a 7" quad rail and install it no prob, but could I cut down the fixed sight without touching the gas block to fit a longer hand rail(non free float)? Without having to replace the gas block? I kno of people who have cut their fixed sights down for the freedom of obstruction.

[AgentTikki]

Yep, a die grinder or a grinding wheel on a dremel like tool is all you need. You might want to remove the FSB first if you want to paint or parkerize it afterwards.

Its an inexpensive mod, done pretty quickly. I helped my friend do one, was pretty easy. He just used rattle can brake paint to touch it up afterwards. Its pretty low profile too so you can put a 15" rail on it and It should slide right over!

[blackguns3000]

So on the front of a 15" rail, how does it mount to the gun? Does it just fit and tighten snugly to that part of the barrel?

[blackguns3000]

By the way agenttikki, thank you this is great news for me. I couldn't be more excited I was kinda thinkin it might not be so easy. Thanks a million! C:

[Jpyle]

Originally Posted by blackguns3000

So on the front of a 15" rail, how does it mount to the gun? Does it just fit and tighten snugly to that part of the barrel?

You will be hard pressed to find a non-free float foreend that will allow you to mount a 15" setup on a 7" gas system. Any conventional handguard will use the delta ring and front cap to secure the handguard to the barrel. A free float setup eliminates both and secures the handguard to the barrel nut leaving the front end open or closed with a cap that's more for looks than function.

What rail are you looking at? There are no 15" gas systems that I am aware of, are you sure it is not a free float?

[Belltactical]

Just curious but why do you want a 15 incher on an m4?

[AgentTikki]

Originally Posted by blackguns3000

So on the front of a 15" rail, how does it mount to the gun? Does it just fit and tighten snugly to that part of the barrel?

I'm saying that you can put a free float rail over your modified gas block. A free float rail or handguard attaches to the upper recieveror at the base of the barrel by the barrel nut. That way when you hold or put any pressure on it, it doesn't move your barrel around.

Now you gotta choose your rail carefully. If you choose a rail that requires you to use a new barrel nut, you will have to remove the muzzle device and gas block. So read up before buying.

I don't think he's going to put a 15" rail on it, just saying he can if he wants.

After helping my friend do his, he put a 12" DD rail on it. It was very nice, but he did have to unpin his modified FSB and remove it and the flash hider.

[AgentTikki]

Originally Posted by Belltactical

Just curious but why do you want a 15 incher on an m4?

Not saying he should do it, but saying he can if he wants to. But I guess he could if he were looking for a mock dissapator look.

[Jpyle]

Originally Posted by AgentTikki

Not saying he should do it, but saying he can if he wants to. But I guess he could if he were looking for a mock dissapator look.

Gotcha. Confused myself, read both posts and somehow came away thinking the OP was looking at a 15" non free-float handguard to mount on a carbine length gas system.

Mock dissipator look is a great idea, the FSP at the rifle length position would serve to anchor the non free float handguards, yet he avoids the cycling issues of a rifle length gas system on a 16" barrel.

[blackguns3000]

Got somethin really cool for this idea. It's a 10.7" quad rail made for the m4 that calls for no modification; no cutting or replacing front sight/gas block. It fits the 7" factory handrail attachment and barrel nut. And extends past it a few inches, so its a mid length quad rail essentially, installs in a minute, military grade aluminum and mounting, and, Omg, only $70!!! I think its brilliant. And what a steal. http://www.combathunting.com/product.cgi?group=12942&product=12977
Actually, check out the pic here: http://www.cheaperthandirt.com/ARR157-7.html
Of course, these pics are not those of my gun, but I ordered last night along with a foregrip and bipod and a couple other small things, so its just a matter of days until mine is equal to or better than those in the catalog pics ;-) Oh yeah. I'll have to change my picture!