Get in touch with a SAKO service rep (in Europe, not North America) by e-mail is what I'd suggest - don't fiddle with 3000$ worth of hardware.
the stock screws should be hand tight only, not torqued down like you do the action bolts. if they come lose during firing, you didn't do them tight enough. I think I usually do mine to about 20 inch lbs.
For future reference, try: info@sako.fi; they will no doubt direct you to the appropriate rep...