Here are instructions from another site.
Please Note: This is not to be confused with the trigger adjustment for the standard Model 77. This is the instructions for the two stage trigger found on the heavy barrel V/T. For instructions on the standard Model 77 trigger, see "Doc's" Model 77 Trigger Adjustment instructions in this tech section.
Webmasters note: This information is strictly for reference purposes only and is not intended for use by anyone other than a qualified gunsmith. The author, nor the webmaster will be liable for any incidents or accidents that occur through the use of this information. In laymans terms, if you are not a qualified gunsmith DO NOT MESS with your trigger. Leave it to the professionals!
Here is how I do it; First make sure the rifle is unloaded (DUH!, yeah I know, but it has to be said)with the bolt cocked and in battery. Back out all three adjustment screws three or four turns.
1. Turn the sear engagement screw(bottom)in SLOWLY until you hear the
"click" of the secondary trigger searing off, STOP immediately. Now raise the bolt handle and back this screw out an additional 1/8 turn.
2. Now lock the bolt down again, and turn the overtravel(middle)screw clockwise until it bottoms against the secondary trigger. Now place and maintain rearward pressure on the trigger, and slowly turn the screw counterclockwise until the trigger sears off(dry fires). Turn this same screw an additional 1/2 turn.
3. Turn the pull weight adjustment screw(top) clockwise, checking every 1/4 turn or so until you get a pull weight of 2 to 2.5 lbs. When you are finished, cycle the bolt HARD, rap the butt on the ground etc., etc. Check with the safety in all three positions. Above all, make sure it's SAFE!
That's all there is to it. Good hunting and be safe.
