Ok, this is a noob question, but I need to ask it.  What is the difference between CAR and M4 style handguards?  I thought they were the same.  Which type of guards are these --> www.bushmaster.com/shopping/uppers/pre-ban/bura2b16m4.asp ?  Can someone explain and maybe add some pics of the two to show the difference.  Specifically ones to fit a 16" barrel if there is any difference in size.  

Thanks

Those are CAR style handguards.

The M4 style handguards are taller and more oval. The original versions had double-heat shields and were designed to protect the user from the increased heat generated by the shorter M4 barrel.

This does protect your hand from heat better; but also cools the barrel more poorly than the original CAR handguards.

The versions sold by Bushmaster and many other companies are the same dimension as the M4 handguards; but often have a single heat shield. To my knowledge, only Colt offers the double-heat shield.

Some people like to mix and match (single heat shield handguard on top for better cooling, double heat-shield on bottom for protection)

Either set will fit a 16" barrel with no problems; but the different handguard heights can affect different aftermarket accessories (usually extended receiver rails).

Thanks Bart... That helps Alot!!

According to Bushmaster they M4 handgards cool the barrel better then the car handgards.

Check out this link:
[url]http://www.bushmaster.com/shopping/handguards/1005-914-4573.asp[/url]

Careful, that kind of thing will get you slapped around these parts. [:)]

According to Bushmaster, a canted FSB has no effect on the gas tube lining up.

According to Bushmaster it is illegal to put even one single full auto part (such as a firing pin) in your semi-auto weapon, even though it in no way changes the functioning of the rifle.

According to Bushmaster, their BMAS system is the best, most rigid, and most modular system around.

According to Bushmaster, you MUST HAVE a taller front sight post if you're going to use an ARMS #40 on a flat-top.

Need I go on?

In this case Bushmaster is right - since "their" M4 handguards have the same dimensions as real M4 handguards; but only have a single heat-shield, they have more internal airspace than CAR-type guards and better airflow than real M4s - both of which will make them more effective at cooling the barrel.

However, they will be less effective than real M4 handguards at protecting your hand from the heat generated by the barrel.