Hi, i have a standard g&p m4a1, with no modifications.

Install Larue Free Float Rail System
Larue Rail System

I would like to swap the handguards out for some Daniel defense lite 9' rails. I plan to make it a free float rail so i will remove the front sight. Do i need a gas block for the rail to be able to 'free float'? If so, i have already picked out my gas block and i am wondering if it will fit in the rail. I will replace the stock outer barrel with a madbull 10' outer barrel.

08-15-11, 00:03. Take a rifle with an aftermarket free floating rail, kneel on one knee, hold it out in front of you horizontally then bring the front of the free floating rail down on your knee like you were trying to break a large branch, there's a good chance it will break at the barrel nut.
LaRue Tactical 13.2 Handguard LT15-13.2. Ideal for 16'-20' barreled uppers that need maximum rail space. The 13.2's length covers all gas blocks, including full-lengths, providing true free-float. Our two-pin proprietary barrel nut system with its locking anti-slip plate, sets LaRue handguards apart from the competition.

I don't agree, it's no more difficult to install than most free float railed hand guards if you have the correct tools. Remove flash hider, front sight or gas block, gas tube. Place upper in a vice block and remove barrel nut, no need to remove the barrel from the upper. Next move the delta ring parts from the stock barrel nut to the new nut.

P.S. Are the threads on the madbull barrel 14mm pos or 14mm neg?
Rail- http://www.airsoftpost.com/product_info ... s_id=32106 System

Install Larue Free Float Rail System

Gas Block- http://www.airsoftpost.com/product_info ... s_id=28779

Larue Rail System

Barrel- http://www.airsoftpost.com/product_info ... s_id=28429