whats this "still reliable after 5000 round's"?
is there a limit to a rifle's life?

Not sure what your question is?
Well anything mechanical wears.
Might have been talkiing about an accurate barrel???????

what if you take really good care of it? clean it after you fire it every time, wont it have a long life? how many year's?

Yes, If an AR is taken care of it should still be in great shape after 5000. I have nearly 1000 through my newest rifle and it still looks new.. shoots great too.

i wanna try and have my ar all my life and it be a dependle accurate rifle the whole time, but i might have to replace the barrell or firing pin and such things a few times , but the main gun will be fresh :)

Osama! your ass is mine motherfucker! ha ha BOOM BOOM!

i love that

Quoted: what if you take really good care of it? clean it after you fire it every time, wont it have a long life? how many year's?

Actually, you can put more wear on your barrel by cleaning it too often than by shooting it.

if your question is: how many rounds will a barrel last? it depends whether the barrel is CHROME LINED or not. when i say chrome lined i'm not talking about a barrel made with chrome and moly but i'm talking about mil spec barrel with a CHROME LINED BORE&CHAMBER. If your barrel is a CHROME LINED one, i read somewhere (can't recall where) that i'd last 20.000, that's inside of mil specs (and of course) we are talkin about a well taken care barrel, with no lack or over cleaning.
Keep your barrel clean, lubed (ONLY WHILE IT IS IN THE SAFE) and you'll have fun for a long long time b4 you have to get a new one.
I hope this helps
HUNTER FROM ARGENTINA
OUT.
oh two more things...your barrel will be chrome lined whether it is marked on it or not, if it is a govt contract barrel i.e. bushmaster, colt armalite etc, and if it's not (chromed) it'd last half of the life of a chromed one.
AGAIN
HUNTER FROM ARGENTINA
OUT.

yea i got a bushwacker :)

I you take car of you gun it wil last as long as you can shoot it.

There will be some lil. cheap parts that you may need to fix(FP,ejector,ect)over time.
And you will need a new barrel about every 25,00-30,000 rounds.

I have 2,500 fired so far with my Bushmaster XM15 car and the only time I had to even pause is when a primer fell out of a shell and down in to my mag.
Other than that the gun run fine, it never "jams" or stops and I can shoot anything as long as (I) can hit it.