In 1881 the US Army went to the 500 grain RN bullet for increased penetration at long distance. As I recall, their test was to penetrate 5" of live oak at 1000 yards.
Dont remember if it was the 1881 Saeco 500 gr grease groove bullet or the big 530gr Lyman, but one was developed to shoot through the horse killing the indian sneaking along the other side.
