Asking a factory rifle to shoot 5 shots at 1/4" @100yds is ridiculous. Asking it to shoot 1" at 300yds is also ridiculous.

But it doesn't hurt to try. ;D

I recommend using IMR7828 with 208grn A-max. Play with the seating depth and you should be able to shoot right at 1/2" at 100yds and should achieve decent groups at 300yds.