They are 300’s.
A fine caliber.
My Elk rifle is chambered in 300 Win Mag.
My longest shot afield was at 600 yards, and it was very strong upon arrival.
Doesn’t the .300 Win Mag have the same energy at 1,000 yards out as a .357 Magnum at point blank range? I seem to recall reading that somewhere. Now that’s a big hitter!