I adjusted mine per the instructions below but wasn't happy with it until I changed the spring as Vic said. While i was in there I found a burr/rough area on the sear that wasn't helping things. With the spring change and a bit of honing mine is quite nice now at 1.5 lb.
From Weatherby's website FAQ:
12. How do I adjust the trigger pull on my Mark V rifle?
A. The Mark V trigger assembly has two socket cap (Allen-type) adjusting screws. The socket cap screw on the bottom of the trigger assembly adjusts for weight and trigger pull, and is for your use. The socket cap screw on the top of the trigger assembly adjusts sear engagement (“creep”), and is for use by Weatherby factory and Authorized Service Center personnel only.
WARNING!! Do not attempt to adjust sear engagement, make any adjustments other than as described below, or modify the trigger assembly in any way. Improper adjustment or modification of any firearm trigger assembly can result in the firearm discharging prematurely due to a “hair trigger,” minor bumps or movement, possibly resulting in serious injury or death. The trigger assembly has been set at the factory for weight of trigger pull appropriate for most shooters. If you require a heavier or lighter weight of trigger pull, adjust as follows:
1. Unload the rifle as follows:
Keep the muzzle of the rifle pointed in a safe direction and your fingers out of the trigger guard and away from the trigger at all times while unloading the rifle.
Move the safety lever to the forward position to unlock the bolt.
Raise the bolt handle and pull the bolt to the rear to extract and eject any chambered cartridge.
Place one hand under the floorplate to catch cartridges to be removed from the magazine.
With your free hand, press the floorplate release to open the floorplate and remove any cartridges from the magazine.
Reposition the magazine follower inside the magazine and close the floorplate.
Visually double check the chamber and the magazine to make sure there are no cartridges remaining in the rifle.
Removal of stock is not necessary. The socket cap adjusting screw is accessible through the opening in the trigger guard, just forward of the trigger.
To increase weight of trigger pull, with a hex key (Allen-type) wrench of proper size, turn the bottom socket cap screw clockwise (when viewed from the bottom) until desired weight of trigger pull is established.
To decrease weight of trigger pull, with a hex key of proper size, turn the bottom socket cap screw counter-clockwise (when viewed from the bottom) until desired weight of trigger pull is established.
NOTE: For safety reasons, weight of trigger pull will not be adjusted below
three pounds. To determine trigger weight requires use of a trigger scale.
After adjusting the trigger to the desired weight, engage the safety and pull the trigger to its limit. Release it slowly to ensure that it returns to the forward position. If the trigger does not return to its position, you have adjusted the trigger pull too lightly.