Here are pics of a new sling we've been working on with Ashley @ Blue Force. This is a prototype, but we are working on the final revisions and should start producing them soon...
The ends are metal HK hooks that can be used with std sling swivels - HK attachment points or paracord (IDF style). Should allow for use on most any combat weapon.
Ashley designed a firing extension that does not require folding and velcro like the IDF style slings. Once you release the fastex the weapon will extend further for shouldering of the weapon. When you need to take it back up just re-buckle the fastex and the weight of the weapon will put the extension back in place.
Webbing is the same as on our other Blue Force slings (like the SOC-C) - 1.25" and pretty stiff so it will not "U bend" after extended use.