The manual does not show any adjustments on the trigger of your gun, however the pull can be lightened by changing trigger springs and stoning the sear and trigger mating surfaces. There is an adjustment screw and by loosening the adjustment set screw and turning the screw in 1/8 of a turn at a time, you can change the pull. Part #39 is the set screw on the following schematic and 72 is the adjustment screw.
You should really have a gunsmith do it for you. Changing the trigger pull will change the sear engagement and the gun can fire when taking it off of safe or by bumping the gun. There are aftermarket triggers that are adjustable and they will make a huge difference in the pull weight, creep and over travel. Timney makes an excellent trigger for your rifle.
I think you would be better off with the Timney trigger and not messing with the factory one. You can install it yourself and they are preset for about 3 lbs.
I hope this helps you,