Many of the BlackRapid camera straps work great as rifle slings. Some that work best are the Cross Shot (shown here), the Curve, and the Sport. And the Sport X comes with a QD mount in case your rifle has a Quick Detach point on the base plate.
What makes this a unique rifle sling compared to other brands and versions, is that this stays put on your shoulder and the rifle slides along the sling. Plus they’re very comfortable.