Specter Gear have models designed to fit standard fixed stock M-16A1, M-16A2 and M-16A4 type rifles as well as nearly all  possible AR-15 variant configurations. 
These slings are 1.25" wide, fully ambidextrous and available with or without an EmergencyRelease Buckle (ERB).  

Colors: Black or Coyote

Specter M16/AR15 Sling

$24.99Price
Specter M16/AR15 Sling