I might have posted this in the wrong place last time:

Hey guys, new to the forum. I bought a Colt HBAR about 3 years ago and havent done much with it. Getting ready to go out to WYO to do some varmit hunting. I would like to know how to setup my HBAR to be a good varmit gun. Looking for a good flat top receiver as well as some different handguards with bi-pod and a muzzle break. Looking to keep the gun as acurate if not more so. I would like to put a leopeuld scope on as well. Thanks for the help, great site!

you probably just need to get some good ammo - check the ammunition forum here - and some good optics for the dogs.

the colt HBAR is likely to be more accurate than you right now until you get way used to it.
then later,  if you feel like the rifle is holding you back and all other requirements are satisfied (good ammo that groups well out of your rifle, good scope), then you can upgrade the trigger, free float the barrel, etc.
most of the colts i have messed with have decent triggers to start with.  if not, let that be your first upgrade.
right now, i'd just pick a good grouping load, set it up with a good, clear scope you like and shoot it, shoot it, shoot it.  spend your $ on ammo for awhile.  

look at Black Hills loads with Ballistic Tip bullets or Hornady V-max loads - its a 1 - 7" twist barrel, lean towards the heavier bullets - 60 grain and up, usually.

and try some cheaper stuff - hey if it groups well with Winchester varmint load value packs from Wally world, go for it!

as far as muzzle breaks, you really don't need them on a 5.56mm HBAR.  increase muzzle blast and teh noise level goes way up.  just run it with a clean muzzle if you're after varmints.

have fun with it!

Thanks marchaira, that is some good information. The main reason I wanted to go with a flat top is for the scope, I figured it would be more accurate then putting a scope on top of the handle, plus it wouldnt have such a high profile. I would at some point like to free float the barrel, but I do agree with getting the proper ammo, makes a huge difference. I have not had time to really play around with that aspect either.  What is a good upper with weaver rail as well as a good scope mount for the handle? Thanks again for the information.

so right now you dont have a flattop?

if you just need an upper reciever then basically any std. upper will do since they should be made to the same specs. i wouldnt mount a scope on top of a carry handle unless it was a compact acog so i couldnt help with that. if you can get away with using std. rings for the scope then do so but if not then the larue spr mount would be my first choice for a qd mount, rra/armalite for thumbscrew mount and if money was not an issue the nightforce mount. some scopes require a good amount of eye relief and the rail estate on the upper sometimes isnt enough so there are cantilever mounts out there to solve this.

Thanks for the reply eklikwhoa,
No I dont have a flat top at this point. thats what I was looking to get. I also have been looking around at the Colt Accurized rifle, not sure if its more accurate then my Comp Match target HBAR but I could tried in my HBAR for the accurized and then just buy the scope and the bipod. I am looking to put some sort of leupold scope on, just something good for 400-500 yrd prarie dog shooting.
Excellent information, thank you.