WTF are you guys on?
Bolt-action? Taking on a numerically superior, better trained force? Gentlemen, I'm pretty sure none of you has any *real* idea what this is going to entail. If we do this, a full-blown stage 3 guerilla war against the state, we're going to be fighting much the same way the IRA fought Great Britan. Yes, there will be some sniping involved, usually against politically important targets, or stragglers from a larger force. Most action will take the form of short, violent, close-range ambushes performed from behind cover against a selected, weak opponent. Supply trains, power stations, banks, isolated military units, etc...
There won't be any kind of "taking to the field" sort of action, at least not until we've a) captured tanks and artillery, and b) trained men on how to use those captured field pieces. Even then, we're not EVER going to have air superiority, so such "field actions" will be relatively few in number. I imagine a very Vietnam-like strategy would work best, building up our "conventional" forces in secret while we conduct harassing guerilla operation in myriad urban environments. The rural areas won't be our battlegrounds, they're going to be our refuge. If a rural "safe house" is discovered, then and only then is there likely to be any kind of military action in a rural setting, and that's going to be a tactical withdrawal under fire.
The best gun to have? Whatever you can use to defend yourself with. No "registered" firearm will be of much use until open warfare erupts, and that's only going to happen if enough resources are obtained to support it, either captured form Federal troops, or provided by a foreign power that recognizes our movement as a legitimate cause and wishes to gain our favor. Make no mistake, we NEED a foreign ally to win. Our forefathers needed the assistance provided by France to win the Revolutionary War, and we're going to need it to win the Second American Civil War.
Don't fret too much about what to buy. *Any* rifle in 7.62x39, .223, or .308 should be fine. Ammo resupply will be available for any of those calibers no matter what. As long as you can use it, and use it well, you should be fine. Even if it's only a handgun, you can use it to get a better weapon later. The key is improving you personal skill level, not what weapon you buy.
Sorry about the rant and biased personal opinions, guys....it's been a long day
Ziggy