Heat is going to be an issue on any free floating rail system.

The rail acts like a heat sink, and unfortunately, Aluminum stores heat very well.  I put Magpul XT panels where my hands will usually contact, and ladder panels where I don't expect to put my hands.

With suppressors, after just 4 full magazines a rail will be too hot to touch with bare hands.  Ladder panels also allow bare flesh to contact uncomfortably hot aluminum: I really just use them to reduce rail abrasiveness.  With non suppressed rifles, you can get about twice that much in rapid fire before heat management becomes an issue.

Mostly, just remember that you have a rifle, not a suppressive fire weapon, and adapt your rifle's set up if you expect to be putting a lot of rounds downrange for whatever reason.  Stubby VFGs are great because they allow the high support hand grip when you want speed and accuracy, and also provide a good place to hold if you're hosing.  Obviously, polymer VFGs do a lot better to mitigate heat migration.

double post