TKs Lancaster. The taper gives the bullet a taper. It is 'square' for 3/8" or so, then a gentle taper - works just great if you don't over think it too much.
I used 310's and was testing 330gr. when I became distracted by other testing. I made the 310 through 330gr. from discarded Fed. .223 cases left all over the range by the Police when they do their ERT training and qualification. The 310gr. (actual 309gr. to 312gr.) shot into 1 1/2" in my first .375/06IMP using what today sounds like a still load of IMR3031 but in that rifle, I had listed as moderate.
Vel. 2,450fps.