The S400 & S410 models all have the same trigger mechanism. It is a two stage unit with adjustment to both stages plus a weight of pull adjustment. It is easy to upset the balance between the two stages and make the trigger inoperable if incorrectly adjusted.
If you have no experience of adjusting two stage triggers seek guidance or leave the trigger as set by the factory
Note! Incorrectly adjusted trigger mechanisms are not covered by the manufacturers warranty it is not possible to test this rifle with a incorrectly adjusted trigger, therefore all triggers leave the factory with correct adjustment.
Warning! An incorrectly adjusted trigger can make the rifle unsafe to handle.
DESCRIPTION OF OPERATION
The s400/410 rifles have a true two stage trigger mechanism this means that as the trigger is pulled the bottom sear gradually disengages with the top sear until the two disengage completely and the rifle goes off. If the pressure on the trigger is released at any point before full disengagement, the bottom sear will automatically return back to full engagement. This type of trigger allows very fine but safe operation because it is the release of the 2nd stage that actually makes the rifle fire. This arrangement is vastly superior to pseudo two stage triggers where the first stage is just a pivoting trigger blade that does not move sears. The down side is that they are more difficult to adjust correctly.
There are three adjuster screws, A-B-C.
The weight of pull adjuster (A) is located in the front of the trigger guard. Clockwise rotation increases pull weight. If adjusted too far the spring will become coil-bound and prevent trigger operation.
The second stage adjuster (B) is the rear screw located in the trigger blade this screw determines the exact point that the 2nd stage starts. If the ist stage screw is incorrectly adjusted this screw may not have any effect.
The first stage adjuster (C) is the front screw located in the trigger blade. This screw determines the length of travel before the 2nd stage starts. Clockwise adjustment reduces the first stage travel.