srtie4k
I think the Remington 700 would be a good series to check out. It's probably the most commonly used long range platform in use in the US.

Bruno747
700's are good, but they are more expensive to "accurize" than others. This is due to the fact that the barrel actually screws into and buts up against the receiver. There is no lock/jam nut, so there is more turning time on a lathe to get headspace and bolt play setup properly. However 750m should be doable with a factory rifle and some good ammo. Reloading ammo to your specific gun will do you well.
 
I would say that you need to put 2k in the rifle alone before optics. Get a upper range Vortex, mid range Leupold, low end Zeiss. If you havent already learn about MOA or Mildot, preferably both and learn the conversion.
 
I tend to prefer 7mm to 300, or 6mm in bullet caliber, but out of the right gun setup properly, either will do spectacular things.
 
If you want to do a reasonable AR build that would get you there, I would pop together a 6.5 grendel/264 lbc. A good 24" with a medium weight barrel and a mega arms SBU Billet upper. Drop an AR Gold trigger in it with a PRS stock. MMM MMM MMM
 
Ill tell you what my long range gun is. It used to be my 300 Ultra Mag then I swapped to my new one. It started as a Savage 114 American in 7mm Rem Mag. I borrowed some time at a buds machine shop and accurized the action on the lathe and put a medium weight shilen barrel on it that is 28" counting the "brake" I much prefer the wood stock to the Tacticool ones they sell on most rifles today, so mine has a leather cheek riser to meet my eye with the Leupold Scope.
 
Total in the gun, $650 (original purchase price), time rented on lathe $100, Barrel $350, brake $150, cheek riser $35 Leupold scope $1200 and some bedding compound I already had on hand.
 
Grand total $2485 and it is pretty easy to keep on steel at 1000m when you get a good rest on sandbags. You should be able to take 500 off a scope and have similar results.
 
Of course keeping with the tradition of nothing totally factory, the ammo is custom load. Running Barnes 168gr LRX bullets with retumbo powder and Benchrest magnum primers.

BF3PRO
 
 
I don't know I really like Spikes Tactical Lowers and BCM Uppers...  I personally go for a forged system rather than billet...  If you do decide to build it make sure you get MIL-Spec and not the commercial spec crap....  Is this your first rifle?  Would you be interested in an AR?  What will your primary purpose of the rifle be?

Nozler
 Shoot the gun your thinking of buying, at least a gun of the same the same caliber ...At a shooting range of course. "Wear hearing protection",,, then shoot it again the next day <<. Some gun ranges have an overhead canopy,that can lead to extensive hearing loss. Shooting such rifles in a more open areas will deaden the primers concussion >" Decibals" but that will not deaden any recoil. If you buy a rifle clean the barrel b\4 u ever shoot it, possibly again Period.. I would hope you've shot a pattern .. If New, then clean the barrel b\4 you ever shoot it & after every shot at least for a box of shells, Clean patches are a Heavens speak. "A Tac Driver is no less or no more." Sk

wrinvert
are you looking for a "bench rifle" or long carry and hunting rifle? I might have something you will want to look at.

wrinvert
my dad and I shot 1000yrd bench competitions with this custom built .308baer heavy barrel on a over built 300 win mag action and 100lbs of lead and 50lbs of mercury cartridges(the absorb recoil for follow up shots) it mounts on rails so we can re-zero every shot on the 2 -piece tri-pod. it's total over kill but @ 1000yrds 10inch ground are a bad day.  

 
if something like this is what your looking for let me know I can help you find a builder. if you just want a factory gun 300win-mag to reach out that far or .338lapua. ruger and Mossberg make some nice stuff. the heavier the better if you not lugging it out hunting.
 

Baltothewolf

wrinvert
Hey i was at my local gun shop today and found a nice 300win mag for $1200ish. Has a nice break on a heavy barrel and custom stock. Also comes with 200+ rounds and only has a mag or 2 through it. Just add optic and go. Lanco tactical, google them and shoot nathan an email.

That's around the price I'm looking for, but I don't have the money right now, I'm waiting for my settlement to be done with my car accident.