So I have a shiny new Colt 6920. I am debating whether or not to throw a RAS II on there.

The biggest question for me involves heat retention: Will a RAS II do a much better job at dispersing the heat from a rapid string or two (and planning to take some classes soon), or are the stock Colt double-shielded handguards going to do the trick?

I am not a huge fan of VFGs, and my system administrator life doesn't call for much use of a weaponlight (though a FSB mount could take care of that, I suppose), so the only real reason I would go with a RAS II would be the heat issue.

What say you? Worth going to RAS II, or stock handguards good enough?

I have a RAS II on my Colt but have used the Colt handguards.

For a string or two you really won't have any heat issues.  Bring mechanics gloves just in case.

The RAS II should disipate heat more rapidly than the standard handguards, but how much & how fast I can't say.

The real benefits to the RAS II are free floating, VFG, light, etc.  The VFG really makes the carbine much more manageable and quick, you may want to give it a second chance.

Don't sweat the heat!

I've taken many carbean classes with the SHITTY Bushmaster single shield hand guards and they were plenty adequate.  The Colt Hand Guards will be just fine.

spend your money on something else.

We have three RRA DEA model rifles (14.5 inch SBR).  They have the Surefire rails and we only use the Surefire ladder rail covers.  I used the rifles for running quals.  There were a bunch of rounds fired and between shooters they sat in the sun on a 100 degree day.

The rail system was almost too hot to touch.  There were no vertical grips, just the ladder rail covers.

Gloves were needed, but after making the suggestion... no one showed for quals had gloves.

A KAC rail cover on the bottom rail or some other full rail cover would have solved the heat problem of being too hot to hold (shielding the heat from the support hand)... as would a vertical grip.

There are two issues here.  Heat radiation via the RAS to aid in cooling the barrel (I am not sure it would make any significant impact on full auto round count before chamber heat would cause cook-offs... extending the round count to cook-off temps), and heat shielding to keep heat away from the support hand.

The heat radiating off the barrel and transfered into the rail system could be uncomfortable.  It may help in the big picture to dissipate heat by transferring it into the RAS but I doubt it.  As far as comfort level, it could still get too warm to hold on long bursts (not an issue for you) or if solar heat adds to the problem.  

In your case... If you just want the heat controlled as it relates to the support hand comfort... the factory M4 double shield handguards would work very well.

We also had Colt SBRs (14.5 M4 barrels) on the firing line.  The stock Colts had the factory M4 double shield handguards... I had ZERO whining from the Colt shooters.  I had MUCH whining from the RRA shooters with the rail system and ladder covers.

Thanks for the outstanding info!

I'll be staying with my standard guards for now. Can get a case or two of ammo with the money that saves ;)