I am new here mainly looking for some components for a mark v I have have for a while and decided to build a 338 norma on. I am looking for the drop box/floorplate to add 1 round with the spring and follower. I also need to know if I can purchase the mark v trr range cert bolt with the knurled oversize knob with the lapua bolt face since no gunsmith seems to offer machining the stock nob to accept an aftermarket tactical knob. Perhaps the part # for the extractor for the magnum face bolt as well since they seem to give out at the worst time so I can carry one in my stock pack. Thanks in advance.