If I was in the market for a new rifle and had my choice….
It would be the 260 Rem OR a 6.5×55 SE “Varmint” model.

I would go with the 260 Rem.  The case fits the .308 bolt face and the .308 mags can be used.

Not that I've shot the 7mm-08, but if I had to choose and NOT exceed the .308 case, it'd be my choice. I just like 7mm more than the 6.5 you get from the 260 Rem or 6.5×55 despite hearing good things about all of them.

6.5 creedmoor

I would get the 6.5X55 Sporter if money not an issue.  great caliber and Tikka does the barrel twist right (1 in  eight) (i kept getting an emoji when i used 1:8

All good products, what tikka base you starting with?
Ok for long range target look at 6.5 series. The 6.5×47 is a winner.but not factory barrel.  If I wanted a semi custom gun I would get the Sporter in 6.5×55. The Sporter stock is nearly as adjustable as the trs although I may be wrong on that.

I love shooting my super Varmint in 6.5 swede on a good day 600m not a problem sometimes we push the 100m range still shooting way above my pay grade
That's my 2 cents worth
Go the swede IMHO

Ok if you are serious about 1k shooting you have to go with the 30 cal and maybe the 338.  Wind is your enemy.if no wind then I say use the 6.5 to 7 mm.  All the wind nonsense makes those big guns the fact. 

.284 Win is the answer to your problems.  You can load from 140 – 180 high BC bullets and easily see off any 30 cal bullet that can be launched from a .308. 6.5 Creedmoor or .260 Rem would be good options too.

Look at the BCs of 6.5 and 7mm bullets and run the numbers and you will see that they can outrun all of the .308 capable bullets, even at long range. For paper and steel that's fine, but for long range hunting I would want a 200+ grain 30 cal or a 162/168/180 grain 7mm bullet.

I re-read this thread and you would be hard pressed to beat the .284 shehane or 7mm-08.  I have not used either but the print is positive.  I would still lean toward the 6.5×47 or .260 .  Good luck and sorry if I sounded like I knew when I only “thought” lol.

I mostly agree. Shehane gives around 3 grains more capacity than straight .284 and is a great option, but dies will cost more and cases need fire forming. 6.5 x 47 is slower than both .260 and 6.5 Creed, which is fine at 600 yards or less, but the extra 100 fish or so will be useful at 1000 yds.

260 Remington Ackley Improved if you're going for 6.5mm

……….but  straight .284 if you want a 7mm. No need for fire forming like with Shehane or .260 AI and much more guts than a 6.5×55 SE.