Trigger talk is something that everyone seems to have an opinion on and that's a good thing. It seems at times, however that those opinions may be malformed or misguided. While not an expert, after having reviewed hundreds of firearms and trained with several models, in different environments and states of mental and physical preparedness at ITTS, Front Sight, CENTER-T, and Thunder Ranch, I too have an opinion about triggers and think I can toss in some thoughts worth sharing.
This is a collection of both maxims and reflections based on my experience, please contribute your thoughts on these topics in the comment section.
The popular thing is to gravitate toward pull weight. This makes some sense in that it's the one metric that every gun and trigger-maker wants to publish, but does it really matter? We stopped measuring pull weights in videos a long time ago because my experience has taught me the pull weight only matters in a few specific scenarios.
It is true that too heavy of a trigger can cause you to miss a shot if your hand is struggling so much that you tighten your entire grip while pressing the trigger. It is also true that a pull too light can be a liability under duress. Trigger discipline or not, when your heart rate is up you may touch off a round before you intend to regardless of pull weight. Though I experienced multiple firefights in Afghanistan, I can not once recall thinking about the clunky GI trigger in my M16A2, or the awkwardness of the trigger on my M203. When your life is on the line somehow those details become less relevant.
The counter to either of those points comes down to training and knowing your gun. Our "Shooting Impressions" videos are our first time to the range with a particular firearm and yet we've managed to shoot most guns fairly well. How? Training and experience has enabled us to adapt quickly to a spectrum of triggers. More than once I've run DA/SA pistols at Front Sight and still been able to be one of the first to get a shot off out of the holster, in double action, because I knew the gun I was using.
Rarely Measured is the trigger reset. That is the distance the trigger must travel forward after firing before it is armed and ready to fire again. Walther Arms is one of the few who talk about it and that's likely because they've got something to boast about. A short reset theoretically makes for quicker follow up shots. It's theoretical because once again it comes down to training and experience. The shortest trigger reset in the world doesn't mean much if you haven't settled the gun back on target yet or don't have the finger discipline to stop your finger as soon as the trigger has reset. Further compounding this is that if you do know your gun, chances are you're able let loose a follow up shot just as quickly on a not-so-short reset trigger.
What really matters to me is a trigger's feel. This unfortunately can't be given a metric for quick comparisons of models, but is the summation of several aspects:
Reach: Does my trigger finger naturally reach the trigger in a comfortable position and is it able to remain in a comfortable position throughout the stroke of a press?
Consistency: Does resistance stack up or remain constant? If it stacks does it feel the same every time? Can I predict the trigger? This can change over time as friction services polish with use.
Predictability: More important for slow, controlled fire than defensive drills, can I feel when the trigger is just before the break? Most triggers have a detectable wall before the break, but walls differ in how thick they are. For some it's just a minor bump in the pull, others feel more like a two-stage and require additional force to break through.
Timing: This is one I wouldn't have believed if we hadn't run so many guns through out Trigger Control Test. Some triggers create a synchronized feel of break and the shot being fired, others feel like there is a slight delay.
The best trigger out there is the one you know. Secret exposed. Learn your gun. For learning the trigger I rank three methods from most to least helpful:
Dry fire. No ammo or facilities required, with an empty gun learn to complete a trigger press without moving the gun off target. If you like to shoot from reset trap the trigger to the rear, hold it there, and use your support hand to reset the action, then get back in position and practice again. Start by trying to run the trigger as slowly as possible.
Training: The most expensive route both in time and money, but running your gun through someone else's set of drills and instruction will improve your capacity as a shooter and greatly increase your understanding of your own firearm as you take what had been a known (your gun) into an unknown (the course) and learn from both of them.
Range Time: Note that this is ranked 3rd. It costs more than #1 and 2, but once you have an idea of what you're looking for it becomes valuable.
What Are you Looking For? This topic gets its own section as I truly believe that most triggers have a situation/application that they serve best in. Light and short triggers are great for competitions, but may be a liability in self defense scenarios. Longer and heavier triggers might literally save a life (or jail time) in self defense, but could also cost a stage or two in competition. Once again, aside from extremes like a 12lb double-action only or 2lb pull with a reset under 0.01", it comes to knowing your equipment. A trigger can enhance your shooting, or make it easier to reach your goal, but in general a trigger does not make or break a good gun/shooter alone.
Curved Vs Straight is a debate that I don't think gets enough attention. It seems lately the trend has been to straight triggers no matter what, as if manufacturers and designers had never considered the simpler, less-expensive-to-manufacture straight trigger was better. Why even bother with the trouble of a curved trigger?
Curved triggers provide consistency. While coming into contact with the trigger and applying pressure the finger is gently suggested into the same location shot after shot. Curved triggers can also reduce the distance a finger has to reach to get on the trigger. A downfall however is that the perigee of the finger's reach also tends to be at a spot that forms an arc during trigger travel.
Flat triggers offer a leverage advantage (assuming the mechanism pivots instead of slides). Regardless of the posted pull weight of a trigger, by placing the finger at the end of a flat trigger more leverage is applied against the mechanism, resulting in a lighter feel. The opposite is also true as the finger moves up the trigger leverage is reduced. As a result, an undisciplined trigger finger may not encounter the same pull feel shot after shot. The leverage factor makes flat triggers excellent for bench rifle shooting.