Actually, the screw that is located between the two triggers on a double set lock does not change the amount of force that is needed to pull the front trigger.
That screw changes the depth of the engagement between the front triggers catch and the rear triggers latch.
Picture it this way. The rear trigger which is spring loaded has an area on it that sticks out towards the front trigger. I will call it a latch.
As the rear trigger is pulled back against the spring pressure this moves the latch down and it pushes the catch on the front trigger forward, out of the way. As the latch moves further down, the catch on the front trigger moves over the latch, keeping it from moving back upward when the pressure is removed from the rear trigger.
There is a screw that controls how much the front triggers catch can move to catch the rear triggers latch. That is the screw between the triggers. If it is unscrewed or totally missing, the front triggers catch will move as far as it can to totally catch the latch.
If the screw is screwed in too far, it will keep the front triggers catch from moving far enough to engage the rear triggers latch at all.
If this happens, with nothing to catch the rear triggers latch, the rear trigger will move forward when the finger pressure is removed and the rear trigger will not become "set" at all.
Notice, none of this has a thing to do with the amount of force needed to pull the front trigger.
It does have a lot to do with how far the front trigger needs to be moved before it will release the rear set trigger though.
Some people think this extra distance the front trigger must be moved is the same thing as the amount of force needed to move the trigger. It isn't. The distance the front trigger needs to move increases but the actual force needed to move the trigger does not change.
While I'm on the subject, here is how to adjust a double set trigger:
With the lock in the "Fired" position, pull the rear trigger to "set" it.
Once it is set, using a screw driver, slowly turn the adjustment screw clockwise (in). If you have a American made Double Set trigger, soon after starting to screw the screw in,the rear set trigger will be released. (Keep your fingers out of the rear triggers way. It will snap forward with a lot of force.)
Once the rear trigger has been released, screw the adjustment screw counterclockwise (out) ONE FULL TURN.
Now, try resetting the rear trigger. It's latch should be caught by the front triggers catch keeping it "cocked".
A light pull on the front trigger should release the rear trigger.
I said "American made" because the set trigger on the Lyman and many other Italian made guns have a adjustment screw that is too short. Because it is too short, it cannot be screwed clockwise (in) far enough to actually cause the front trigger to release its catch from the rear triggers latch. This seems to be some sort of "safety" the Italians have dreamed up to keep you folks from adjusting the front trigger far enough to just barely catch the rear trigger. Obviously if the front trigger is just on the verge of releasing the rear trigger, the slightest bump or jar of the gun could cause it to fire.
Some people have replaced this screw on the Lyman and other Italian made guns with a longer screw and their triggers can be adjusted like the American made triggers.
OK. Tomorrow there's going to be a pop quiz on this to see who was sleeping or thinking about Betty Lou's blouse and not paying attention during my lecture.
That screw changes the depth of the engagement between the front triggers catch and the rear triggers latch.
Picture it this way. The rear trigger which is spring loaded has an area on it that sticks out towards the front trigger. I will call it a latch.
As the rear trigger is pulled back against the spring pressure this moves the latch down and it pushes the catch on the front trigger forward, out of the way. As the latch moves further down, the catch on the front trigger moves over the latch, keeping it from moving back upward when the pressure is removed from the rear trigger.
There is a screw that controls how much the front triggers catch can move to catch the rear triggers latch. That is the screw between the triggers. If it is unscrewed or totally missing, the front triggers catch will move as far as it can to totally catch the latch.
If the screw is screwed in too far, it will keep the front triggers catch from moving far enough to engage the rear triggers latch at all.
If this happens, with nothing to catch the rear triggers latch, the rear trigger will move forward when the finger pressure is removed and the rear trigger will not become "set" at all.
Notice, none of this has a thing to do with the amount of force needed to pull the front trigger.
It does have a lot to do with how far the front trigger needs to be moved before it will release the rear set trigger though.
Some people think this extra distance the front trigger must be moved is the same thing as the amount of force needed to move the trigger. It isn't. The distance the front trigger needs to move increases but the actual force needed to move the trigger does not change.
While I'm on the subject, here is how to adjust a double set trigger:
With the lock in the "Fired" position, pull the rear trigger to "set" it.
Once it is set, using a screw driver, slowly turn the adjustment screw clockwise (in). If you have a American made Double Set trigger, soon after starting to screw the screw in,the rear set trigger will be released. (Keep your fingers out of the rear triggers way. It will snap forward with a lot of force.)
Once the rear trigger has been released, screw the adjustment screw counterclockwise (out) ONE FULL TURN.
Now, try resetting the rear trigger. It's latch should be caught by the front triggers catch keeping it "cocked".
A light pull on the front trigger should release the rear trigger.
I said "American made" because the set trigger on the Lyman and many other Italian made guns have a adjustment screw that is too short. Because it is too short, it cannot be screwed clockwise (in) far enough to actually cause the front trigger to release its catch from the rear triggers latch. This seems to be some sort of "safety" the Italians have dreamed up to keep you folks from adjusting the front trigger far enough to just barely catch the rear trigger. Obviously if the front trigger is just on the verge of releasing the rear trigger, the slightest bump or jar of the gun could cause it to fire.
Some people have replaced this screw on the Lyman and other Italian made guns with a longer screw and their triggers can be adjusted like the American made triggers.
OK. Tomorrow there's going to be a pop quiz on this to see who was sleeping or thinking about Betty Lou's blouse and not paying attention during my lecture.
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