Sometimes I hunt wrapped up in the sling - it's faster to get in any position that way and it doesn't preclude me from taking a rest.
Yep. I use the Wilderness Rhodesian, keep my off hand through the loop while carrying on the move. With practice I can get into it and be ready to shoot in about 2 seconds. Faster than trying to find a rest if time is of the essence. Less noise, too.
