Thanks for sharing your experience and knowledge. I am truly impressed with you making shots at those distances. I assume you are dialing up on your scope at those distances.
Those distances are beyond my capability off a cross sticks. Also, where I hunt, a 300+ yards shot opportunity is rare if not non-existent due to terrain restrictions and overdevelopment. The maximum distance norm at the places I hunt is about 225 to 250 yards. In addition, a light jacket fast expanding bullet is desired to prevent ricochets.
Some of the old timers I use to meet (now I am an old timer

) used cartridges like the 218 Bee and 22 Hornet and were quite successfully around here due to the lack long range of shot opportunities. One old guy I knew was quite successful with a 222 Rem and 50 grain bullets. Both the 222 and 223 Rem with 50 and / or 55 grain bullets seems ideal for this area.