Don't shoot .264 Win Mag but I am pretty knowledgeable of 6.5mm bullets. If you are going to be pushing the limits of the .264 you are going to need a bonded or mono metal bullet for close range shots, cup and core bullets are likely to separate at those impact speeds, but truth be told you could cut back to 260 rem speeds and still drop any deer that ever lived with standard SGKs/SSTs/Core-Lokts....etc if you wanted to.
I have recently become very fond of the new 140gr Deep Curl bullet it is a bonded bullet sold for a cup and core price and the accuracy has been fantastic in my Sweed, TSX and TTSX bullets are great but very very picky on seating depth making developing handloads challenging. I hope that helps.
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Is the deep curl and new issue for the grand slam? Haven't really looked at them.
Oh and I forgot to mention the Nosler Partition, another tried and true bullet in 6.5mm, pricy but worth every penny for high impact speeds, the rear portion of the bullet is separated from the front making a bullet blow up almost imposable even at 3400fps+ speeds. Expansion is similar from 2200-3000+fps making it a remarkably consistent performer with more then adequate penetration for any deer, actually the 140gr are better suited to elk class game. I have 125gr Partitions for deer hunting in my 6.5x55.
I would have agree with you about the nosle patitions, the only thing that I don't like about them is the soft lead nose and how it deforms it the magazine, that is why I switched to the accubonds in the 7mm stw.