You need to take the time to learn how to shoot. There are very few people that are just a natural with any kind of firearm. You have to practice. When you are first learning, use a 22 long rifle. The ammo is usually rediculously inexpensive (they make good rodent guns too) and readily available just about anywhere that sells ammunition.

Like Wiz said though, 30/30 is great IF you know how to use it. Ammo is cheap for them too but you have to be careful what you buy. If I buy pre-made ammunition (with a couple of exceptions for a few of my rifles) then I buy either Federal or Hornady. I have had the best success with those two over many years of shooting. You need to think about your terrain when you buy ie. what is the weather usually doing? Is is high wind all the time, is it really humid or is it dry or in between? Am I going to be shooting over long distances, short distances through heavy brush both? What do I usually hunt with this caliber? Having any sort of firearm is a blessing in a survival situation, but also knowing how to use it is better. There are several handguns that are great for these situations as well.

 

Anyway, before I got off track here, what I meant to say was learn how to shoot first, then get picky. You can usually antique rifles at most sporting goods stores and some hardware stores.  The Enfield rifle is a great rifle, whichever model you get (I used to have an Australian Enfield years ago). I think I saw a picture of one with a scope on it that Jim took and posted. I will have to go look again to make sure that's what is was. You can sporterize these rifles to make them lighter. They are 303 caliber.

 

One of my favorite rifles is the M1. They still make these and they are fabulous weapons, tried and true. Military surplus firearms are great, just keep an eye on what you buy and there are a lot you can get that are from europe with funky calibers that are hard to find the ammunition for. A very good friend of mine reloads and he is exceptional at it (been doing it for almost 30 years). I am starting to get into it, and it's cheaper than buying by a landslide. I have reloaded shotgun shells for years, but am just now starting to study brass cartridge reloading. Something to think about, especially if you shoot a lot.