The only commercial 350gr. I've shot were Barnes originals, many years ago - with .049" jackets. They were shot in a .375H&H and went 1 1/2" at 100 yards.

The 340 to 355gr. home made bullets I came up with, using .223 brass also shot into 1 1/2", but at 100 meters - using either the WW or pure lead cores.

I've not tried 300 TSX nor heavier TSX (didn't know they made one) - only the 270's and cannot really see a reason for anything heavier than the 270's.

They are already spears.