I think that we have entered into an era where everybody thinks they already know everything, and the study of gunfighting is no different. The way to use the pistol's trigger to its greatest utility is not up for debate, opinions, or discussions. The trigger's use is determined by its design. A 1911 trigger is different from that on a Beretta 92. And a Glock trigger is different still. The trigger that comes on a mass produced factory pistol will never be optimal, but it will generally be safe. But safe is relative and overachievers want better...but better within reason.
Lets look at its phases and what constitutes the better trigger systems available to you on a combat pistol today.
Trigger Take-Up (also referred to as Pre-Travel)
Take-Up is any movement of the trigger toward you that does not cause the sear or striker to move and does not engage the mainspring. Take-up is most evident in a two stage trigger. The initial movement from the resting position up to the point where you feel resistance is Take-Up. The point where resistance is felt is often called "The Wall".
Shooters are often adamant about exorcising any take-up, but take-up is actually irrelevant to good shooting. As long as that take up is relatively "weight free", it will lead up to the "wall" and never be felt again until you remove contact with finger on the trigger, and then decide to reestablish it. Eliminating take-up/pre-travel on a combat trigger is the height of foolishness.
The Wall is the point where the trigger action first engages the resistance. This could be a sear with a traditional SA or DA pistol system, or with a striker such as on a Glock.
The "wall" will require additional weight or effort applied above what was necessary to manage the take-up. This is the area of most importance for accurate shooting. As more effort and force is applied by way of the trigger finger, the pistol is "steered" or moved out of position. This force is necessary to reach and achieve the Trigger Break, but sometimes, fearing the Dewey Crow shooters out there...and their inevitable lawsuits, gun companies seem to strive to make triggers heavier and heavier.
The trigger need not be light, but it cannot be heavy, nor can it be gritty or creepy. The travel it takes and the force exerted to break through must be smooth and be free of the starts and stops of grit and creep. Quite a conundrum.
I like my striker fired pistols at about 3.5# to 4#, but not heavier. I can make a heavier trigger work, but it takes more effort than I think is necessary for safety and accuracy. I like a 9# DA trigger and on these weapons, I have run subsequent SA triggers whose weight would never be considered safe on a striker fired pistol.
Trigger Creep is any movement of the trigger, upon reaching the wall that contributes to reaching the break, but has a gritty, dragging, and well...creepy quality to it. The transition from "wall" to "break" should be sudden and as some would say, have a "surprise" quality to it. Trigger creep retards that quality and drags out the time it seems to take to achieve the break.
When you apply additional pressure upon meeting the Wall, it seems that the mainspring/striker spring begins to compress and the metal on metal parts begin to drag on each other inconsistently as if there was sandpaper involved - or steps - until eventually the break is achieved. Sometimes when this is being discussed, the words “gritty” or “mushy” are used to describe the trigger's feel.
If you haven't guessed, trigger creep is not a good thing and good pistols do not exhibit this.
This is the point of trigger operation where the striker is released, or where the hammer begins to fall. Jeff Cooper once described this event like a thin glass rod being broken in half.
Good word choice. A good trigger is free of creep and breaks cleanly - like a glass rod.
Over-Travel is any continuing trigger movement after the Break. To be honest, although there is a great deal of discussion on this by the propeller-head types, if one has been trained to break the trigger and then reset as the pistol returns from recoil, anything but ridiculously extreme over-travel will be virtually imperceptible. Another thing that leads to trigger problems, accidental discharges, and malfunctions is the elimination of over travel vis-a-vis these adjustable triggers. I've yet to see an adjustable trigger not become mis-adjusted in a fur day training session.Unless it is exaggerated, over travel is irrelevant.
Trigger Reset is the trigger being allowed to move away from you, as powered by the internal mechanisms of the pistol. The trigger re-engages the striker, or trigger bar/sear as soon as the slide cycles back into battery. Trigger reset is something you allow to happen, rather than something you cause. You do not exert any force on the trigger for it to reset. You will feel the weight of the springs returning the trigger to its original point against your finger, moving the trigger forward until the action resets.
The quickness and travel required to reset contribute to the speed of additional shots. Reset on a DA/SA action, such as the SIG P-226, returns the trigger to a single-action position. The mainspring is already compressed, and the weight required for the next shot will be considerably less. Reset on a striker fired pistol will replicate the condition where you have moved through take-up and are at the wall again.
Just as it is important to know how to physically operate the trigger, it is important to intellectually understand what is happening with the weapon, mechanically. And also to understand what a better trigger really is, and what it actually provides you.