Ok you want to get lock and loaded in no time?
Here is how.
I am first level and already got 2 combat shoties, minigun, laser rifle, metal armor and combat helmet.
Of course enough ammunition as well.
If you are burster, need smg, cruise around ncr and search for marauder vs ncr encounter.
If you want to get better stuff, go near broken hills and search for unity vs rogues, or vs broken hill caravan.
Turn on both modes od real time, dont get killed or shot.
Wait after survivors loot corpses and then loot rest of the stuff.
Quite easy, this way you can get armed just in first level and go hunting muties molerats.
Even better advice for smg characters is to get ASAP grease gun, because you can craft 100 45 cal. just for 2 gunpowders, easy and cheap
Good luck