300 yards is not that difficult buy a AR-1O bolt rifle in a 6.5 Creedmoor that is ported ,put a good bench scope with target knobs / turrets like a Nightforce or another good brand . buy a good swivel bench bi-pod too.
WTH is an AR1O bolt rifle?
Don't be the darkness.
America will perish while those who should be standing guard are satisfying their lusts.