The Davis Deerslayer is a Double Set, Double Lever (or blade) trigger that can be shot either "set" or "unset". It doesn't care.
To fire a gun with this trigger left "unset" you will just ignore the rear "trigger" and use the front trigger.
The trigger pull force needed to fire the gun with the set trigger left unset will depend on your lock and the location of the trigger, relative to the locks sear arm. The sear arm is the part that sticks out on the inside of the lock. The "lever' or blade(s) as I prefer to call them pushes up on it to cause the lock to release.
This force may be only a couple of pounds or considerably more.
If the rear "trigger" is pulled to "set" the trigger assembly it compresses a stout spring.
As the rear trigger is pulled, a catch on the front trigger will latch onto the rear triggers blade and hold it in the compressed position.
A very light pressure on the front trigger will cause the front triggers catch to release the rear triggers blade.
When this happens, the spring forces the rear triggers blade up rapidly where it hits the sear arm and releases the lock.
Setting the rear trigger and releasing it by pulling the front trigger will not damage the trigger assembly.
If the cock or hammer is in the fired position (down) it won't damage the lock either.
This allows one to practice using the set trigger on the uncocked gun as much as they like.
If the lock is at the half cock position when doing this setting and releasing the impact of the rear triggers blade on the sear arm may break the sear or the half cock notch in the tumbler.
Needless to say this is not good so, do not set and release the set trigger when the guns lock is in the half cock position.
There is a screw hanging down between the triggers and many people think it adjusts the pressure needed to fire the set lock.
This is totally untrue. It does not adjust the pressure on the front trigger.
What the screw does adjust is the engagement between the front triggers catch and the rear trigger latch.
If the front triggers catch deeply engages the rear triggers latch, the shooter will have to pull the front trigger more to fire the gun. Notice, I did NOT say he will have to pull it harder, just further.
If the screw is adjusted too far in, the front triggers catch will not engage the rear triggers latch at all so the rear trigger cannot be set.
A worse condition is where someone has adjusted the screw so that only a tiny amount of the front triggers catch will be engaged with the rear trigger.
In this condition, the slightest bump or jar can cause the triggers to release and fire the gun.
Hope this helps some of you folks who have never used a double set trigger before.