I just took delivery of a Sheridan made Accumark in 300 Winchester Mag. The port size is only a bit over Saami OAL (3.34").  The bolt doesn't retract enough to clear the port and the length of the internal magazine box completely limit the OAL on my present loads.  I presently load 3.65" for a couple other 300 Win mags that shoot perfect at that length and that length easily chambers in the new Weatherby.

Will a 338 mag box fit without too much trouble?
As far as port size, I either need to get the bolt to retract further or extend the cut-out in the front side.  It won't even eject my 3.65" loaded round.
Yes, I can load shorter but I would rather not have .40" freebore.  Again, this is a 300 Win Mag so pressures will not be an issue.
Thanks in advance!