"Ok, I'm going to address the several suggestions for a rifle/carbine again:
1)Even for the 4lb Kel-Tec Sub 2000, you are talking the weight of an extra tent and sleeping bag.
How 'bout ditching the tent AND the sleeping bag?
2)The suggested mode of carry (strapped to the side of your bag), makes it essentially useless. The weight distribution of your bag would be wwwaaaaaayyyyy off. Try a 33 mile day with 4 extra pounds hanging off the side of your pack. Try a 13 mile day in the White's, or an 18 mile day in the rocky parts of Pennsylvania. Ain't gonna happen.
How do you think you are going to deploy a weapon that requires you to take off your pack, unfasten, and bring to aim in an emergency? Further, to suggest a sling or hand carry is equally ridiculous. There is no way with the terrain of the A.T. that you could carry a rifle safely in your hands, and achieve the daily distances necessary for a Thru-Hike.
Funnily enough I seem to recall a fellow by the name of Daniel Boone (and many others) did more or less this same thing some 200 years ago on an undeveloped/unmaintained trail carrying a 10 lb longrifle + lead shot + gunpowder without the benefit of hiking boots, fancy hiking duds and packs, GPS, topographical maps, cell phones, or likely even a compass. So "Ain't gonna happen" and "There is no way with the terrain of the A.T. that you could carry a rifle safely in your hands, and achieve the daily distances necessary for a Thru-Hike" seem to be more commentaries on lacking abilities of modern day outdoor enthusiasts than inabilities of humans to survive in less than ideal terrain. They did it back then, it can be done today if folks would only apply themselves.
3)Weather - This was one of the wettest years on record. How do you suggest I keep the rifle dry? Covering it is only going to add more weight.
Do what those fellows did, meticulously maintain your weapons, sleep on your arms, and use plenty of lubricants (animal fats in their case) to coat the metal.
Alternative:
Small .380, .38 Special, or 9mm pistol in the hip belt pocket of my pack. Right where my hands are, unzip, ready to go. Weight? Well, carrying even an extra ounce sucks, but if you insist on carrying a firearm on a trip like this, its the way to go."
Folks should do what suits them, but it always kills me to see modern outdoors enthusiasts who can't fathom survival in the "wild" without all their modern luxuries and gizmos, to the point of claiming it can't be done without said aids. It can be done and has been done. Moderns (and I'm speaking in general here, not attacking the op) are just too lazy, timid, or unwilling to do it.