The best thing I've found, (next to someone else carrying my rifle), is the "GunBearer" by KIFARU! In two words, IT WORKS!
After 3 back packing Dall Sheep hunts, 2 w/a rifle & 1 w/a handgun, I decided there must be a better way to carry a rifle. So began my search to find a way to carry my rifle: securely, comfortably, fast into action, & lower (so the barrel isn't catching on all the brush as I work my way up the mountain). Price was my last concern, like I said short of hiring someone to haul it for me!
I happen to be looking through the KIFARU website to check out their light weight Rambling rifles & Kifaru Tipis (light weight tent system), when I found what I was looking for. The KIFARU Universal GunBearer is simple, secure, light, fast into action, & cheap I was a little skeptical at first (which comes natural for me), but after using it last fall on my Moose / Caribou hunt I am extremely happy!!
Just about anytime you use a pack and carry a rifle you can use the "GunBearer", and you'll be glad you did.
Good Hunting, Hiking, & Back Packing -
Del