Finally got my M4 built, and need a sling for it. I've got a RRA stock, and have access to a side sling adapter if it will help.

I'd like a good sling that would also work as a good all around tactical sling.

Anybody got any good recommendations? What should I look for in a tac. sling?

And not to sound real stupid, but what purpose does the side sling adapter serve?

I really like the Giles sling from the Wilderness. www.thewilderness.com It is wide enough so that it is comfortable. It is very well made. It allows you to carry the carbine in a cross carry position and then present it rapidly. Also if you have a malfunction, it allows you to drop the rifle and draw your pistol. It is a modified H&K sling, so it allows for several methods of carry.
The side sling adaptor allows you to have a tactical type carry, without the rifle hanging upsidedown. The standard sling swivel is of course on the bottom. The old type top carry adaptor was just a peice of wire that hooked into the front sight assembly and the sling went through it. The down side was it often covered the front sight in a rapid presentation.

I use a Boonie Packer sling, got it from Bushmaster.  It is reasonably versatile, allows a cross carry and the use of both hands while keeping the rifle handy across the front of your body and oriented properly.  It uses a loop of ballistic nylon that you pull over the barrel and front site, with a buckle on the bottom of it that installs into the regular bottom sling swivel.  The strap of the sling is looped through this "loop" that encicles the barrel/handguard, and you don't need the side sling adapter.

It seems to work well for me.

Hope this helps.

[img]www.eagleindustries.com/Images/Prodimages/m_TAS-3.jpg[/img]
Check out this sling from eagleindustries.com / I have one and I am quite happy with it.