What Caliber for 600yd Whitetail? (New rifle Build)

I'm looking to build a 600yd hunting rifle. I'll be starting with at Rem 700 LA left hand, trued. I'm planning on a 24" bartlein barrel. I'm not scared of wildcats or Ackley Improved either. I reload so, I'll be developing the loads. The current rifle is a 270win, but I'm thinking there is more bang for the buck in LR performance and aftermarket support. Most of my hunting is within 350yds or so, but I'm wanting a reliable option out to 600yds. This will double as range gun for some fun and probably run 2-300rds per year on the high side.

I'm leaning towards a 260rem or 7mm 08 in the LA. These guys not restricted to mag length can be pretty impressive.

I currently load for:
308, 7mm Rem mag, 7mm 08, 270 win, 223
And I have a 6.5 Creedmore on order for my son. We'll be loading for it as well.

Must haves:
-Long Range Support in brass and projectiles, at least in the manufacturing side. I'm not expecting everything to be in stock. (I'm not against fire forming good brass)
-Decent barrel life ~1800-2000rnd minimum
-Enough kinetic energy for deer at 600yds

Would like to haves:
-cross over powders or projectiles to current reloading stock
-Factory ammo options are nice, but not required.
-Something that is powder efficient
-No one ever complains about low recoil...

Feel free to add details of barrel length, twist, reamers, and load data.

Thanks very much for the info!
Wow only been nine hours and already 30+ responses.
You are asking a LOADED question.
Everyone knows that we are a big fan of the .260 rem AND also the 6.5X284. If you are reloading go with either 6.5s and Lapua brass is available. Some will say just go with the .260AI instead of the 6.5X284. Your decision. Personally, I say the .260rem and the 6.5X284 for past 600!
140 SGK with H-4350 1:8 twist for the .260.

Goodluck with ever you choose
Len & Jill
 
You are asking a LOADED question.
And in my mind,only one correct answer.
But my answer leaves 2 of your requirements out… barrel life and efficiency….
But it makes up for that with wow and impressiveness.
RUM.

Imagine a 300 yard zero with 5" of drop at 400. 16" at 500, and plenty of VELOCITY to kill big game at 800yards.
Recoil…., not with a 124 grain projo and good muzzle break…..
And When you add the probability of lighting strike style kills out to 600, there really are no arguments that can change my mind.

@ButterBean for reassurance
 
Since you do actually want to build another rifle and happy to incorporate another chambering go for a .280a.i. because it fits the bill and is a sleek looking cartridge.

There is factory brass, off the shelf dies and it's gaining popularity. Cause it's just a better 7mm-08 . Horses for courses this will send the right pill longer better faster and you won't have anyone telling you the 7-08 might not feed in the long action.

Mine is a Tikka with an IBI carbon wrapped barrel 1 in 8.5" twist that shoots nice groups after being carefully assembled by a gunsmith.it has a Precision Defence industries featherweight stock .

I'm wrapped in the cartridge , I'd like to have the same in a nice classic looking rifle.

My 7mm-08 is in a compact package Tikka CTR and makes a good truck gun.
 
And in my mind,only one correct answer.
But my answer leaves 2 of your requirements out… barrel life and efficiency….
But it makes up for that with wow and impressiveness.
RUM.

Imagine a 300 yard zero with 5" of drop at 400. 16" at 500, and plenty of VELOCITY to kill big game at 800yards.
Recoil…., not with a 124 grain projo and good muzzle break…..
And When you add the probability of lighting strike style kills out to 600, there really are no arguments that can change my mind.

@ButterBean for reassurance

Are we allowed to discuss Hammer Projectiles here?

The only 124gn .30 cal I know of are the 124gn Hammer Hunter that I run in my .308.

The 124 gn Hammer Hunter projectiles are very accurate in my .308.

The Big Fella and his mates love their RUM cartridges and they run Hammer Projectiles. The Hammer projectiles are excellent. I use Hammer Projectiles.

I ordered more Hammer Projectiles for my .308.

Guys over on another forum run Hammer Projectiles and get really high velocities from them. Can't be good for barrel life but these guys are getting a kick out of it.

I did Hammer a couple of Fallow with my .280a.i. using Hammer Projectiles but mostly impressed by the 124's in my .308 for nice accurate load.
 
Any reasonable cartridge will work. I remember back in the early 1960's when I was in the military, shooting the M-1 ( 30-06 ) at 500yds with mil ammo. I believe something like 150gr ball at about 2750. No problem at 500yds. It's all about the person squeezing the trigger. Any average simple cartridge like a 25-06 , 6.5-06, 270, or heaven forbid the 30-06. There is abunch more I left out. You of course can spend a lot of money on a one of a kind custom rifle if you prefer. In the end it works out the same. A good shot, game on the ground regardles of the cost of the rifle.
 
Any reasonable cartridge will work. I remember back in the early 1960's when I was in the military, shooting the M-1 ( 30-06 ) at 500yds with mil ammo. I believe something like 150gr ball at about 2750. No problem at 500yds. It's all about the person squeezing the trigger. Any average simple cartridge like a 25-06 , 6.5-06, 270, or heaven forbid the 30-06. There is abunch more I left out. You of course can spend a lot of money on a one of a kind custom rifle if you prefer. In the end it works out the same. A good shot, game on the ground regardles of the cost of the rifle.
Hespco, you left out .308.

For us it's been a military cartridge so it's become mainstream . Heaven forbid someone use a .30-06 for hunting in 2023, haven't you heard the latest hype?

I get the feeling many Americans cut their teeth on a .30-06 for hunting. Well those born before 1990, yes, that's so last century but it has some good history and a solid reputation.

I consider the .308 as "Common as Muck" thing is I keep one because factory ammo is always available, and it's never let me down. I just wanted something more, something that sounded more prestigious and not so "Common"

Common or not to.308 and .30-06 kept us free and defended our nation's.

Happy hunting
 
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