B23
Well-Known Member
it's a tightneck and a longer throat, the bore rider was developed with the lead in being a little different as far as I understand and usually helps get 50-75 more fps. I ordered on in 300RUM and 338Lapua.
Just read a bit about it and it sounds like it's Kiff's version, somewhat-ish, to the +P throat design, yet different. Not really so much a lot of freebore or really long throat but maybe more of a hybrid design.