The 17 K and the 17 AH are different rounds. If I rember correctly the difference is in the shoulder angle. The 17 AH is my all time favorite small varmint round. With 10.4 gr. of powder I`m pushing a 19 gr. Calhoon bullet at 3,600 fps. Max. point blank range, plus or minus 2 1/2 in., 290 yrds. A real little lazer, but presure jumps very fast some when working up a load you need to go in .1 gr. steps.