For anyone seeing out a great 264 Win Mag load for a 1:9 twist, after much experimenting, I've settled on a great consistent, accurate load. This weekend I shot at 700yds in 10mph wind, prone off a Harris bipod. 4-shot group under 6" . Could not be more pleased with it.

Nosler brass
Hornady 120gr ELD, seated 3.245" , 0.005" off lands
Federal BR Mag primer
70.0gr Ramshot Magnum 3250fps
Ramshot burns cool & clean, meters great.

Rifle
Remington Sendero
Timney Calvin Elite trigger 8oz
Nikon X1000 6-24 X 50mm scope

140 Berger’s shot well in the three I have loaded for. Ballistic tips and partitions did great too. I load a Nosler book max of IMR 4350 with the Ballistic tips now. They kill deer and pigs

Mine shoots the 130 accubonds so well I haven’t tried anything else.

In all my other rifles I’ve switched to copper solids. Would like to try the 100 ttsx and the 127 lrx in this one.

Good to Know. My 8 twist like a 140 AB on top of a heap of 7828SSC. But I just competed a 9 twist.

Still shooting this load and with good results. Here in Michigan, Ramshot Magnum powder is available and only $26-27/lb, considerably cheaper than most powders. Magnum is a fine ball powder much like H380, easy to meter and it burns very cool, unlike RL33.
I'm going to try this working with 123gr ELD Hornadys, should work as this gun shoots 130's equally well. The 1-9 twist will not shoot boat tails, but flat base Core Lokt 140's are decent however not as accurate as the 120/130's.
Forgot to mention that the rifle is also bedded.

My Sendero loves the 130 Accubond sitting on Retumbo. I have killed lots of animals with this rifle and load. I see no reason to change.
My old Sako loves the 140 NPT and Retumbo. I use this rifle for hunting in the timber or woods.