I backpack in non-bear country and I carry a S&W .357 Model 65. 3" with fixed sights. 158 grain JHP's.
I'm more worried about the two legged critters than much of anything else.
At night when I'm in my tent it is in its holster, next to my Strealight in the corner of the tent by my head.
I probably have 300+ nights tent camping and have never had to use it but I can tell you I feel better having it there.
Great flashlight is a must also.