Same bolt, gunsmith opened up diameter on lathe them milled bottom corners, purchased 221fb extractor from cz, and using 221fb magazine, single set trigger is amazing, longest kill so far was on a ghog at 380 yds, with a witness, 5moa high 1moa left, 25gr hor. jhp at 3850fps. My 100th ghog this year was 345yds, 20gr vmax. HIGHLY recommend this cartridge, cant see spending upwards of $1600 on gunbroker for a Remington