Mark take all three, and a shot gun the sand grouse are a hoot, they fly like teal on steriods and are the size of doves. The 375 is just right for zebra,eland, and blue wildebeest.
In my gun the load was 75 grs of rl 15, the
270 gr tsx drop like a rock between 250 and 300,
and like a big rock pass 300. You may need to push out to 300 or so depending on cover.

JD