Here's my 2 bits.
I received my 375 AM in time to shoot 4 shots through it last thanksgiving. I then had to put it away until the spring of 2012 as I'm away from shooting and hunting until then. But that's a good thing.
Components are the same as yours except the bbl which is a Pac Nor 30" which seem quite sufficient.
I got a 270 AM from Kirby about 5 years ago. It was a less than a half MOA up to about 400 yds where the wind started whipping my butt.
I'm happy I went with the 375 AM because:
- It shoots a 350gr pill the same speed as the 270 AM shoots a 195 gr pill.
- It shoots the 350 gr pill as flat as the 270 AM shoots the 195 gr pill.
- With the large PainKiller brake recoil is just noticeably more than the 270 AM
- I can spot shots, easily, from 100 yds to 1K. The scope didn't move more than 10 MOA at the shot and settled on the divot after the shot. It WAS a big divot.
Its hard to beat the 338 AM (at the moment). I don't expect this situation to last long though. There WILL be some better offerings than the 350 SMK one of these first days. Lead core bullets, that is.
I'm happy with the decision to go with the 375 as now I don't have to look back regarding thumping power @ long range.
Oh, and BTW I use an RCBS Rockchucker press. Not a problem.
I get the components to Kirby and never expect to hear from him until the project is finished and its time to exchange green backs. I'd let him select the action, unless you already have the Bat. Two consecutive extremely good shooters from the same smith in extreme cartridges doesn't seem unexpected by any means.
Good luck on your decisions.