ahpd1992 said:
Taurus makes a 4" 8 shot revolver in 22mag, I might be mistaken, but I think you can shoot 22lr out of 22 mag revolver. Their inexpensive, but probably weigh more than 18oz.
You're mistaken
. You cannot shoot .22 lr out of a .22 mag chamber.
Going for a short hike overnight some plinking might be fun. Going for anything more than that and your back will regret that you decided to carry plinking ammo. Ounces count and you'll only want the gun and ammo needed for defensive purposes with you.
Don't worry about black bears and the whole getting between a mother and her cubs things is about grizzlies, not blacks. The to are worlds apart in terms of aggressiveness and protectiveness. I've seen video of unarmed researchers tagging black bear cubs. They chased mom up a tree where she just sat and watched as her cubs called for help from below. Other than two legged predators the most likely problem will be sick or rabid medium sized animals like racoons, coyotes, etc. For that I would want more than any .22. .22 mag is about the same price as .38 ammo so there is not real advantage to it. You can also reload the 38 and 357 cutting the cost dramatically, you cannot do this with rimfire. Also consider that centerfire ammo is much more reliable than rimfire. I'd go with a .357 loaded with a good 158gr LSWC or a heavier 180 - 200 gr offering from Buffalo Bore, Double-tap, or Cor-bon.
Check out the S&W Mountain Lite. It's a scandium frame 7 shot .357 that weighs in at about 18 oz. It can be equipped with laser grips which would be a worthwhile addition. Not a cheap package but not insanely priced either.
Whatever you get you simply cannot beat the Safepacker holster from The Wilderness
http://store.thewilderness.com/index.php?cPath=51&osCsid=27icareaso8i4bh3vm8afn37i7for a backpacking holster. Besides the obvious protection it provides for the firearm it can be carried on the wide hipbelt of the backpack which will dramatically improve the carry comfort of the gun thanks to the dispersion of the weight. It also looks like a binocular or gear case and not a holster so everyone you encounter on the trail doesn't know you are armed.
Another great backpacking revolver would be a Ruger SP101 in .357 with a 3" barrel and Crimson Trace grips. It's just a little over your weight limit.
Another consideration would be a 10mm Glock. Again in a safepacker but I would add a laser/light combo to it. You can add a .22 conversion kit for plinking.