Magpul showed us a concept they called the Railed Sling Attachment (RSA) earlier this year, and after some minor tweaks, it is now shipping. The idea behind the RSA seems pretty straight forward, build a piece of metal that attaches to a rail that has a loop in it.... not overly difficult, right? I would agree, but Magpul worked the angles to allow the RSA to mount to the top rail, and angle slightly downwards. The circular portion which the sling clips onto has no sharp edges, so fastening the sling directly to it should prevent no problems. Any clips, latches, or other mounting hardware that your sling comes with should as well, with the sole exception being if you use a QD push button.
The heavy steel construction and its ability to mount on any of the rails while still being low profile should give this mount options on weapon platforms aside from just the M4. Magpul states the RSA handles over 300lbs in stress testing while weighing 1.26 ounces and costing under $30. As with all things Magpul, its made in the USA.
