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Now, my spelling really sucks, but I think you might try to write and spell a little better to get your posts taken a little more seriously. We get a great many "kids" on here that post garbage and I know I pass up some posts that just seem to be less than serious.
What i would like to build here is sort of a sniper rifle.
The AR-15 isn't a great sniper rifle. They are accurate but the ballistics will limit you to some degree. If you wanted a "Tactical" rifle you probably should have bought a better barrel as a chrome linned 20-inch barrel will limit your performance before you even begin. I would want a Stainless or Molly barrel myself and if you are only going to shoot from a bipod I would go with a 24-inch barrel.
I no i want a colt lower. I need to no if there are different models of lowers to suit my needs. I also need to buy a complete lower beasue i dont no how to put it together this will be my first Ar if u havent guess already.
The advise you were given previously is very good as I have owned Bushmasters, Colts, Eagle Arms, and Armalites and all of them are very good lowers. The best way to learn what the AR-15 is about is to buy a stripped lower and put it together. The tools you need are cheap and the process really doesn't require much skill at all. Hell, I think I have put four together now.