I made a single point sling for my paintball marker the other night. Just used cobra knot. Used split rings to attach to the marker, but depending on wear I may just use a loop of paracord.
“A human being should be able to change a diaper, plan an invasion, butcher a hog, conn a ship, design a building, write a sonnet, balance accounts, build a wall, set a bone, comfort the dying, take orders, give orders, cooperate, act alone, solve equations, analyze a new problem, pitch manure, program a computer, cook a tasty meal, fight efficiently, die gallantly. Specialization is for insects.” Robert Heinlein
"There's this new thing called Situational Awareness!" Sterling Archer