I carry a .44 mag with a 4" barrel for bear protection. I have two holsters for it, both made by Diamond D Leather here in Alaska. I am super happy with both and highly recommend them.
The first is a chest holster which has a very loyal following up here and elsewhere, it's is called their Alaska Guide holster.
I use this holster 90% of the time. It fits under the top of my waders perfectly but is still easily accessible.
I had them make a hip holster as well for when I am hunting with binos on my chest. The chest holster is less than ideal and I prefer to have the binos handy but will want a pistol for bear protection in addition to my rifle most of the time.
Their hip holster is the called the Alaska Hunter and I would recommend the drop loop (pictured) as it is more compatible with backpack waist straps. I went with the hammer thong for retention rather than the strap on each holster. Each holster has adjustable tension screws to dial in your preferred amount of retention which is handy when you are pushing thick brush and don't want the hammer thong on in case you need it quick.
I've been very happy with the products and service especially. I've taken then a few custom projects and had some changes made to my chest holster and they have always been timely and great to work with.
http://www.diamonddcustomleather.com/