Q: "What about trigger mods that don't change pull weight?"
Yesterday we had a good question come in from Jonathan I., and I thought I'd share both the question and my reply here:
I recently listened to your thoughts on trigger modification on the Ballistic Radio Podcast and had some addition questions that I was hoping you could answer. You mentioned that specifically reducing pound weight could provide significant cannon fodder for a prosecutor, but what about an aftermarket trigger which allows a smoother trigger pull (ex. adjustable pre-travel & over-travel), but yet keeping the stock pound weight? Do you think it is more so the weight reducing that is the key factor, or simply the act of modifying the trigger at all?
FYI, you can listen to the referenced comments from my appearance on the Ballistic Radio Podcast by clicking to my Youtube version of that appearance. You'll brought directly to the referenced portion of the interview by clicking here. This post will make more sense if you listen to that relevant portion, which lasts about 6 1/2 minutes. (Alternatively, you can listen to the interview in its ~45 minute entirety from the start by clicking here.)
Now back to Jonathan's question: what about trigger mods that may make a trigger smoother or diminish slop in the action, but that do not change the pull weight of the trigger?
I presume Jonathan is referring to things like installation of a Travis Haley "Skimmer Trigger," a drop in trigger unit for Glock pistols. The Skimmer promises a much cleaner trigger action, but also offers an option that maintains the Glock's nominal 5.5 pound trigger pull.
(Similarly results might be obtained by polishing contact surfaces of a trigger mechanism--I wouldn't know, I'm not an armorer or gunsmith. Also, this post is not an endorsement of the Skimmer Trigger in particular, as I have no personal experience with it whatever; I reference it here for illustrative purposes only.)
In short, I have far less concern about modifications to the trigger that do not influence pull weight than I do about modifications that meaningfully decrease pull weight.
It's important to keep in mind that if you use your PDW for serious purposes it is highly likely to be subject to scrutiny by a forensics firearms examiner (and such examination is a near certainty if you've killed someone with that firearm).
One of the tests that will absolutely be conducted on that firearm is a measure of the trigger pull weight, and that pull weight will be noted using simple to understand numbers denoted in pounds: 3.5 lbs, 4.0 lbs, 5.5 lbs, 7.5 lbs, whatever the case might be.
This is a very easy metric to measure and to communicate, and for a prosecutor and jury to understand. Thus if your Glock trigger measures at 3.5 pounds solely because you've installed a "BRAND Y" trigger unit for that specific purpose, and a Glock OEM trigger would have measured at between 5 and 6 pounds, that's a substantial variance and one that's not hard to communicate and understand.
On the other hand, if all you've done is smooth the trigger, but that trigger still requires between 5 and 6 pounds of pressure to discharge the gun, then there is no change in the obvious metric of trigger pull weight.
There is a change in the smoothness of the trigger--but there's no simple, standardized metric to evaluate smoothness. This makes it much harder for a prosecutor to weave a narrative centered on trigger smoothness that would be harmful to your claim of self-defense; a task that is quite easy when it comes to trigger pull weight.
One important caveat is that changes to smoothness that also affect how the gun discharges can still be as harmful to your claim of self-defense as might a substantial decrease in trigger weight. Mess around with the hammer spring, trigger spring, sear, and disconnector of your 1911 to "smoothen" the trigger and end up with an unsafe sear engagement that could lead to a negligent discharge, and that is very likely to be spotted and used against you in court.
The same caveat applies to removing the entirety of the trigger take-up--there should always be some discernible take-up before the trigger reaches the point at which pressure is actually causes functional engagement of the firing mechanism contact surfaces. (In any case, over-travel is far more of a quality concern with triggers than is take-up.)
The best option, of course, remains finding an OEM trigger that works for you without modification, as I mentioned on the Ballistic Radio interview.
OK, folks, that's it for this post. If any of you have questions of your own, feel free to send them to my attention at firstname.lastname@example.org.