Fallout is the only shooter type game I've ever really played. As such, I'm a real idiot when it comes to the real basics about what the different guns are good for. I don't use any energy weapons, just guns.

I'm only on lv 5 so far. Help me figure out which guns are good for what, and when to use which? Which are best for the first shot from long range against a single enemy? What about multiple enemies? Close up? So far this is what I seem to have found.

*I usually use the varmint rifle for my first, long ranged shot. It seems to have the best range of anything I've found so far, but otherwise seems pretty weak. I put it away once the enemies notice me and are approaching.
*I tend to use the 9mm and 10mm (depending on how much ammo I have) most of the time. They seem to fire quickly, accurately, with decent range.
*magnum seems to take too long to reload to be useful
*I found a submachine gun which I thought would be awesome, but the few times I've tried it seems like I NEVER hit anything, and it takes a million shots to take down even a weak opponent.
*I've got a silenced .22, when should I use it?
*Also had caravan and single shotgun, but couldn't seem to find a decent use for them. I'm sure I'm missing something.

Ideally, I'd like to carry 3 to 4 guns max...one for long range, one for general use (multiple opponents) and maybe a couple others for backup or special scenarios (IE, 9mm for when I run out of 10mm ammo, or silenced for trying to pick off one target without alerting other near targets?)