A while back my uncle (Marine, Vietnam) had a 303 and dusted a buzzard on the ground about 250 yards away with open sights. I don't recall any info on that rifle other than it was a sniper rifle or that make was a sniper rifle. It looked old and was heavy but he took excellent care of it. I think that a 303 is a good choice but I know nothing about the loads. GOOD LUCK.