I had an Uncle Mikes sling swivel barrel band on a barrel . the sling got wrapped up with a sand bag and removed the band suddenly and unexpectedly..I usually attach the sling the forearm, this allows the sling and forearm to be used on several barrels.
Will your set up affect accuracy, short answer,MAYBE ! If it is a hard kicker, probably.Try a few shots with a sling attached and the fore arm on bags. Then a few without the sling.you'll get the answer real fast. jh