In my experience, the torque on the action screws can sometimes make a big difference, and sometimes not. It's generally the last thing I work on when seeking better accuracy. Proper torque is not, from what I 've seen over the years, caliber or bullet weight sensitive, so once you've got them properly torqued, the rifle should be good to go with everything you feed it. The improper torqueing of the action screws can upset the harmonics of the barrel, so I just snug 'em down "finger + tight," and spend my time with seating depth, primer selection, powder type and charge, and proper case preparation. The effort expended in these areas has always paid more accuracy dividends than experimenting with action torque settings. The only notable exception to this is tuning the Ruger #1 series of rifles, which display a LOT of sensitivity to the torque level of the forearm screw.