The entire idea for the Contractor pack was so we could mount an AK, M4, M249, M240, 870, etc with the attachments -- damn one guy used it on a RPG...
Its a good setup.
BUT I tend to forget not a lot of people have 8 or so weapons they can take with them...
The VCAS is an excellent 2 pt sling -- but not something I would use for a M249/C9. It will work though.
With PBA the need for a paddled sling is nil as the armour will spread out the pressure anyway.