What are some non verbal indications that someone is good with guns (any and all)? Like, how someone holds a gun, their stance, where their holster is, etc.
In most cases it’s easier to know when someone doesn’t know what they’re doing. With that, there are enough that I wouldn’t pretend to be able to create an exhaustive list. The big ones that will send anyone with firearms training up the wall are trigger discipline and barrel control.
Trigger discipline is about keeping your finger off the trigger until you are ready to fire. It’s a really simple thing, and something everyone handling a gun should practice. Hollywood hates it. Or at least, some directors in Hollywood (apparently) think their actors should have their fingers on the trigger at all times, “because it looks more dangerous.” Which, you know, it actually is. Stupidly dangerous.
Most people who know what they’re doing will rest their index finger along the frame over the trigger. This isn’t the only way, some will simply have their finger sticking out at an awkward angle (and a lot of people will do that during reloads).
Barrel control is keeping the firearm pointed in a safe direction at all times. “Safe,” is a bit of a loaded term here, since, if your goal is to use the gun on someone, you’re going to be pointing it at them. Again, this is basic safety. This is a little more involved, because no matter what you do, the gun will be pointed somewhere. The important part is remembering that, and not pointing the gun at someone’s thigh when you’re not using it.
As with trigger discipline, this is an incredibly basic element of gun safety, that a lot of people who don’t know what they’re doing will easily miss.
There are a lot of other potential tells, someone who drops their magazines rather than retaining them, probably doesn’t know what they’re doing. (This is the practice of discarding a partial or empty magazine when reloading, instead of keeping it.) TV and film love presenting people dropping mags, probably because it looks more dramatic, but it is a pretty good sign that someone’s only education came from mass media.
Concealment isn’t cover. This is one of the few that does tend to separate trained shooters from untrained ones. In a shock to no one, bullets pass through objects in their environment. Taking cover means far more than hiding behind a car door or couch.
So, concealment means you cannot see your opponent. Cover means they’re hiding behind something that will take a bullet. Most of the time, just because you can’t see someone, doesn’t mean you can’t shoot them. Someone hides behind a wall in a home or office? Yeah, you can shoot straight through that. Drywall, almost all furniture, most parts of a vehicle, most garage doors… none of that will stop a pistol round. When you start dealing with rifle rounds, even things like exterior walls start getting iffy. Trained shooters will fire through concealment. Amateurs who learned how to shoot from Call of Duty and reruns of old Arnold movies will try to take cover behind a couch.
Firing until you run dry. This is a little trickier because trained shooters will do this on the range. No one’s shooting back, and you’re going to immediately repack the mag anyway. In the field though, emptying your magazine is a seriously dangerous situation. Reload partials when you have the opportunity to, don’t wait for it to run empty, and have a non-functional gun when you need it.
The problem with all of this information is; it doesn’t really answer your question. It tells you things to look for with someone who doesn’t know what they’re doing. Not how to identify someone who really does. This is because it’s far easier to identify things that an incompetent shooter will do, rather than tells that are exclusive to someone who really knows what they’re doing in contrast to someone who has a basic understanding of gun use.
Some of these also aren’t easy to operationalize. For example, with stance, There’s Weaver, Chapman, Center Axis Relock, Modern Isosceles, and many more. There isn’t a, “correct,” or, “elite,” way to do choose one of these, and many experienced shooters will tailor their stance to match the situation they’re in on the fly. The exact way they do that, or if they choose something that isn’t a functional stance, like Gangster Style (holding a handgun horizontally at arm’s length), can tell you about their training and how comfortable they are with a gun, but it’s not something you can easily explain in abstract. (At least not without going into all of the pros and cons of the various stances, and spending a lot of time going through all of the debate on the subject.) There’s also a lot of blending between some of these stances, and “adapted,” “reverse,” or “modern” variants of them.
It’s easy to distinguish someone who doesn’t know what they’re doing from someone who’s had some basic training, but distinguishing between someone who knows what they’re doing, and someone who is actually good with the weapons can be tricky.
I am sorry if that doesn’t really answer your question.