I haven't used the Winchester 64gr, but I have used extensively the Sierra 63gr SMP and 65gr BTSP.
I load them over Either Reloader 15 or BL-C2. 25.5gr of RL-15 will get you 3,000fps to 3,100fps depending on the barrel length. 26.0gr of BL-C2 will give near equal results.
If the barrel shoots them well, under 1-moa is the norm with my last two .223's running them around 0.5" 5-shot at 100yds.
I've shot a considerable number of deer with them with complete satisfaction. You'll normally get a 1" exit wound and little to no tracking depending on your shot placement. Performance has been good out to 250yds. I haven't shot a deer further than this with bullets heavier than 55gr but indications are that it's still a matter of shot placement,shot placement,shot placement.
Did I mention that shot placement is important?; such as with other similar cartridges such as .243, 6mmRem, .257Roberts, .25/06 , .30/30, ect....................
If your barrel is a 1-12" and especially a 1-14" twist, you may not get good accuracy with the 65gr BTSP. My Remington M-7 has a 18.5"bbl with a 1-12" twist and shoots the 65gr BTSP quite well, (Under 1-moa) even though Sierra recommends a 1-10" or quicker twist.
The Winchester is however a semi-point like the 63gr Sierra (which it was developed from) and will shoot acceptably from a 1-12" twist.