Seems a little contrary to go with Defiance AnTi and then a 3b, not bad but contrary. I have a 300wm GAPmspun up for me on their defiance extreme hunter action, so its milled down to lose weight over their branded deviant action. I did a 23” fluted 3b bedded into a manners carbon stock. With NF lightweight rings (Integral bases) and NF NXS 5.5-22x50mm, it weights 10.4# unloaded.
if I were to build the same rifle today, since it’s a hunting rig, I’d go lighter. It’s not meant to be a sheep rifle. So not expecting it to finish under 6lbs bare, but even for moose, I’m backpacking and carrying the rifle longer distances and wish it was lighter. Today, I’d go with the AnTi and either a #2B or 3 contour fluted.
I have a hammer of a 338 that Jared at APA built me a few years back and I foolishly went with a #4 comotif, it’s just too darn heavy for my kind of hunting, so it about to ship out to Dallas at Lane Precision to get a carbon wrapped barrel, since the barrel channel is already opened up.
Looks like your getting good parts together, should be a fun rifle. Another thing to consider is total king though your options and choices with whatever smith you are using for the build. They can be a huge resource as well.