I don't think so .According to Bells writings ,a tracker would carry a spear over his shoulder which held the Rigby barrel pointing down .This way Bell could grab the weapon in a quick second hanging in front of him.But of course as I was not there one can never be certain but Bell did not like slings .He contended that a hunter or his bearer should always carry the rifle in their hands (or the spear method) Saying a sling made a hunter lazy and could get him killed and also caught on things in the bush. Bell was constantly doing exercises with his rifle on a march pointing it and simulating an encounter. As a Recon Marine we also forbid slings on our rifles on patrol for the same reasons. When we needed a sling when helocasting ,climbing, jumping into a hot area or doing hydrographic surveys we used makeshift 550 cord ,but on patrol always carried our weapons in our hands.