Look into the 6.5mm cartridge class for 1000 yards the ballistics are much cleaner.
Go the ranges that hold the competitions you want to participate in and see what calibers are doing the best. 6.5X47 Lapua, .260 Remington, 6.5 Creedmoor etc use considerably less wind, recoil less than the .308 Winchester.
Some people have problems with the .308 going subsonic before the targets at 1000 yards doing goofy inaccurate things as they transition.
The Armalite will have a 26" barrel which is good, and with a healthy dose of a stick powder behind a VLD or Sierra bullet 175 grains or heavier will give enough velocity to get 1000 yards above the speed of sound.
Yep got four of them.
Two Iron Brigade Armory Chandler's in .308. One in a McMillan A3 the other in an McMillan A5. Both have 26 inch Hart SS fluted barrels.
The A3 has a Leupold Mark 4 4.5-14 X 50 Mildot and the A5 has a Premier Reticles Second Generation Leupold 4.5-14 X 40 Mildot.
Blaser 93 LRS2 in 300 Win Mag. Leupold Vari III 6.5-20 X 50 Mildot
Armalite AR10 SASS fitted with a Leupold Mark 4 8.5-25 X 50 Mildot.
The .308 with a muzzle velocity of 2650 the 175 gn Sierra Match Kings will stay super sonic out to 1000 yards.
The .300 win mags are running 2900 fps with 190gn Sierra Match King.
Yeah I have a few...shoot at least one of them weekly.....
I have two modified Russian SAIGA...
one in .223 and one in 7.62X39
Then I have my "hog gun" ( I hate them things) which is a old Russian SKS 7.62X39....deadly accurate and knocks them hogs on their butts...
Then I have various shotguns/30-06/ single shot .223 (Grandsons rifle)....pistols etc......
I go through about 2 thousand rounds of .223/7.62 ammo per year....