If ya wanna go domestic and old school....
work up to 42.5 grains of 4064....that will get you to 3400 fps neighborhoods, depending upon barrel length....
My nosler book and Hornady book both show a max between 38 and 39 grains with 80 gr cup and core bullets. Hornady online shows a max of 36 with a GMX.
Barnes doesn't have data online for 4064.
I'm not trying to get max velocity. I'd be happy at 3000-3200.
Anybody else use 4064 and 80 gr ttsx?
Edit to add:
I found several old topics here using google and several of you guys were using 41 and 41.5 grains of 4064 with excellent results. I guess I'll work up to 38 or 39 and see what happens.
