I have a Kenai chest holster from Gunfighters Inc that I really like, and I also have a Kit Bag from Hill People Gear that I really enjoy. It carries a gun, spare ammo, and a few goodies, too.
Real use gear for backcountry travelers
hillpeoplegear.com
It works well by itself, or with a pack, and can also "dock" to your pack straps so it's riding on the front of your pack straps and counters the pack weight. Kinda cool.
I have the big one that will carry a 5" 1911 or xTen with SureFire X300 attached. Wife has the small one that just hold her .357 snubby and a couple speed loaders.
I have not found a way to make it work with binos on my chest, so I wear it more when backpacking than when hunting.