I got up to the war at hoover dam and now i cant get out of the place i have to kill the legion guy at the legate camp i dont have any stimpacs left and my guns are out of ammo what can i do.

PS it didnt say i'd not be allowed to get out there.

Accept defeat and drift into the wasteland a lone wanderer who failed his mission. j/k

Are you saying that you can't get into the Legate camp after fighting your way across the dam, or that you're lost inside of the dam and can't find a way out?

i cant kill the guy in legate camp because i got no stimpacs and barely any ammo and there is like 12 legion people in there including the boss guy.

I'm pretty sure before the hoover dam battle a big warning message popped up on your screen telling you something like "Point of no return". That should have been your cue to back out and stock up on supplies.

You might just have to reload to a previous save. Without any way to heal at all, and no ammo, you'd have to be a god to pull off a win here (I'm assuming your unarmed/melee skills are bad).

i have got ammo just not alot

Oh!....uh... you might have to revert to an earlier save and prepare a better plan. Stock up on stim-paks, doctor bags , and a variety of ammo for the weapons you plan on using. A good tip is to sell all your unwanted items, weapons, and armor for life saving supplies before attempting to finish out the main story. Stock up and prepare for the worst. Goodluck!

You could try to go up the dam and loot everything, legion sometimes drops stimpacks and they will have some .308 ammo and usually shotguns as well.

I assume you're playing on hardcoe mode? Because if you're not, there's nothing that would prevent you from carrying TONS of ammo and aid (most of which is not weighted in hardcoe mode)

Also, you will have to revert to an older save, and stock up prior to the battle.