CAR vs. M4 upper differences?

[RicVa]

What are the differences between CAR and M4 uppers? I haven't been able to really find this info here or on ar15.com. Is it just the different type of handguard? I am buying an upper kit soon and would like to know the difference. The Model1Sales kit for the M4 is $40 more than the CAR - why?

Just to clarify...I know the military M4 has the shorter barrel, I'm talking about the civilian 16" barrel. Thanks.

Thanks.

 

[natedog]

http://www.thehighroad.org/showthread.php?t=32515&highlight=CAR-15

 

[Bartholomew Roberts]

Since each manufacturer has a different idea of what makes an "M4", it is going to depend on the manufacturer.

For example, a Colt (real) M4 would have a 14.5" 1/7 chrome-lined barrel weighing about 2.0lbs. It would also have the fatter M4 handguards

What Bushmaster calls an M4 will have a 14.5" 1/9 chrome lined barrel with a permanently attached muzzle device. The barrel will weigh about 2.0lbs but it will come with standard carbine handguards.

Other manufacturers will have slightly different variants; but basically it means an M4-profile barrel in 14.5" or 16". For all practical purposes, the main difference is that the M4 is about 0.5lbs lighter than the 16" HBAR.

 

[Kharn]

When I was shopping for an M4 a few months ago, there were also multiple barrel profiles called "M4":
14.5" lightweight (the issued profile, same diameter under the guards as the M4 cut)
14.5" medium (not skinny under the handguards, I think its about 0.750" the whole length except the cut)
14.5" HBAR (~1" under the handguards)
There might be a few others, depending on manufacturer. The medium profile were said to be the hardest to find.

Kharn