I found a couple quickloads for a similar round, 1.850" case length, 2.350" C.O.A.L. based off of 30-06 brass. The 300gr .44 xtp was going around 2200fps at 60kpsi. IDK if you want to push them that hard in an ak, maybe drop the psi down a bit since the bolt thrust would be more than the x39. The pressure graph on them was in time which makes the pressure spike seem more gentle/vs the more useful barrel length which is good for port placement. Look at other big bores built on the ak action and you should get a good idea on where to place the gas port.