I was just wondering if I should buy a Car-15 instead of a M-4 due to the barrel needing to be 16 inches and the Car is and the M-4 is 14.5 with an extended Flash Hider.  I would think a little more accurate but I am still new at trying to find my own.  

Scott

if you get a 16 inch barrel then you wont have to have the flash supp perm attached.then you can have an easier time changing out things and more options.like gas blocks and free float rails.when it the FS is perm you loose some choices because now you need 2 piece parts and if your barrel is 16 then you just unscrew the FS and do what ever easier.just depends on your need or what you like and weather or not you may change your mind later.

You need to read the boards more.  

CAR15 barrel is 11.5" + 5.5" flash hider= 16"

M4 barrel is 14.5" or 16"