M70 build need sugestions

[rhino519]

so ive noticed that ive been defending my position to build a rifle as oppose to buy a new one in my previous thread, so building it is.
but now i need some input into specs of this rifle, to surmise, its a 30yr old M70 .300 WinMag, resting in a houge stock,

im planning stick with the caliber and shoot 190-200 gr bullets, at about 2850-3000 ft/sec, what would be the best/most optimal twist rate for a 26 in barrel?
I thought about going with heavier bullets so I could deliver Joules up to 1500-1800m but after second thought i realized i dont have a place where i could practice shooting that far, so i can easily downsize and save some $ in the process
groove number? 4 or 6?

 

[hometownhero]

10 twist will stabilize 210gr berger. The 215 and 230 say 9 twist.

 

[baker42]

My old 700 used to love 220smk in a 26inch 1-10 twist... was making 2744fps. I didn't have too much trouble at 1500m, more wind trouble then anything. It was an easy gong ringer at 9-1200m with good wind calls.

Could have sent it faster but the rifle gets what the rifles says it likes!

 

[rhino519]

thanks for input guys, the barrel maker suggested the same, guess i'll turn this thread into pic thread

 

[BigUglyMan]

Pretty sure that ATRS used a 1-10" twist RKS barrel on my 300 project.