what's the best action for a 338 lm build?

[Pdvdh]

With respect to opinions, I checked with Kirby Allen and J E Custom via private message. Both were comfortable with 1.250" breech diameter. I now understand that your personal recommendation starts at minimum 1.300".

 

[Edd]

With respect to opinions, I checked with Kirby Allen and J E Custom via private message. Both were comfortable with 1.250" breech diameter. I now understand that your personal recommendation starts at minimum 1.300".

They and a lot of others are willing to use a 1.250" breech with a 1.125" thread. Many people are satisfied with marginal shoulder widths, some are not. I'm one of the ones who isn't.

 

[hemiford]

Am I mistaken, or do the Weatherby Mk-V actions have a 1.0625
barrel thread tenon ? The 378 series magnums have the same
boltface diameter as the 338 LM.

 

[Edd]

I think you are correct.