Not trying to be rude, but MY definition of backpacking is parking your car, putting on a pack containing every item you will use, walking a trail or planned route for several miles, then sleeping. Wake up, repeat.
Earlier this summer, i went on a two night backpacking trip with a friend. I brought food, a stove, a tarp, a sleeping bad, and 8 liters of water because there was no water source on the trail. Thats 20 lbs of water alone!!!
There is no way I could have handled carrying a long gun of any sort comfortably. Call me a wimp. I also didn't bring a handgun. I wouldn't have minded adding a squirrel to my diet but carrying a pistol added unnecessary bulk and weight. I might bring one next time provided we can find a stream or source of water.
Pretty much, i don't believe those who are carrying shotguns and rifles are actually "backpacking". Camping, bring anything and everything because there is a bigger risk. Backpacking, i can't see carrying anything over a small .38.
HB