I think yes and no. The fitness and coordination are definitely good, but I don't think martial arts helps you with guns anymore than dance or something like that. I have a bone to pick with martial arts in general, at least how they're taught in the US. I believe they're virtually useless for self defense.
I did Tae Kwon Do for about six years. I started with Karate, and while I wasn't in it for very long, I have enough experience with it to know it's essentially the same genre. So they're both for all intents and purposes the same thing. The school I was in taught Jiu Jitsu as well, so I'm familiar with what it's all about. Of the three, I think it was by far the most practical. At the time though, I was more interested in the exercise and competition than any practical application. I never saw it as something practical, besides keeping me in shape and being a pastime.
To be blunt, it's 90% BS, and in my opinion it's a scam. The schools lead you to believe that the higher belts are taught practical self defense techniques, and that's just not the case. The forms get fancier, and you can start learning weapons (totally impractical ones) at black belt, but it's just more of the same. It's all about the belt system because that's where the money comes from, and that's what I mean about it being a scam. There's nothing that I know now that I didn't know as a white belt, besides forms that are about as useful as interpretive dance.
With time and practice comes ability, but it has nothing to do with belt testing or those useless forms. I've also seen plenty of black belts get their clocks cleaned by white belts in the ring. And by the time I was a green belt I could do everything. Everything from there was gained by time on the bag and in the ring, and learning forms for belt tests just slowed down my actual advancement. However, even bag work and sparring are pretty impractical. Am I saying I want to take a 360 back kick to the face? No, of course not, but I also don't want to get kicked in the knee, or lots of other things you're not allowed to do in the ring that will happen in a real street fight. And don't require you to be an athlete to accomplish...
Martial arts is also inherently a cult. You practically have to worship the master, despite the fact you're paying him, and there are dozens of pointless rules to follow and a bunch of Eastern mystical mumbo jumbo. Most schools even require the students to clean the Dojo after class. And here's another part where the scam comes in; you can't ask the master to teach you something specific. You have to wait for him to say you're ready, and most things are restricted to belt levels, which translates into paying for testing just to learn something new. Which would be fine if I worked for him, but if I want to learn something specific it's my time and my dime. What it boils down to is they don't want you to know what you don't know. They string you along as long as they can to keep you thinking there's something cool and practical you're going to learn when you're a higher belt. The lower belts are actually not even allowed to see black belts training; they have their own classes, and if they practice their forms during an open class they have to do it in another room. Most schools will even divide lower ranking belts, so you have classes for white to green, green to red, etc. The whole point is to keep the illusion going that the higher belts know cool useful stuff that you will learn once you do enough forms and pay enough money for testing. It's just more of the same.
Then there's the breaking of boards and bricks. I'm here to tell you that
anyone can do it. Your 80 year old grandma can do it. It's just a show to make you think you're getting your money's worth during testing. The boards are very dry pine, and the bricks are baked in the sun beforehand. Believe me, if they offered any real resistance their insurance would never let them do it, as people would be leaving with broken hands and feet. I once saw a ten year old child break a brick with his fist, and he was on the scrawny side for a 10 year old. I've also seen five year old girls break boards like they were nothing, because they are nothing.
You are not allowed to touch a weapon until you're a black belt. You can't even touch rubber training knives or guns, so no learning to defend yourself against those for at least five years or so, depending on how often your master deems he needs to let you test to keep you on the hook.
I'm sure there are lots of people who will get their feelings hurt over this, but it's a scam, a cult at best. I would suggest finding someone who teaches Krav Maga with no BS. Even those guys have adopted the standard formula though, with belts and the whole nine yards. Like I said, that's where the money is. People just want that belt to wear around the dojo.
You might have some success with private lessons. Most instructors are masters in multiple disciplines, and they do know a thing or two. They're capable of teaching practical self defense when they want to. I would just tell them up front you're not paying them to join a cult or get belts or adopt their religious beliefs. Tell them you want to learn down and dirty self defense, no funny costumes, no BS. If they have a problem with that, then they're not your guy. And tell them you'll do the pushups and jumping jacks on your own time. Make it clear you'll be warmed up by the time the lesson starts and you want a full hour of real instruction, not general fitness training. And don't let them put you in front of a bag for an hour practicing the same thing over and over. Practice can happen on your time. They'll come up with every excuse in the book to slow you down, so don't stand for that. If you feel like you're spinning your wheels at any point it's time to find a new teacher. They will try to dominate you and get you into a subservient role (it's what they were trained to do), so don't let them forget who their employer is. They don't have any knowledge that dozens of other people in a hundred mile radius don't have, so don't be afraid to take your business elsewhere. And again, if there are belts, tests, or a hierarchy of rules then run and run far.
I'm not trying to pick on anyone. If you enjoy it then all the more power to you. And if it keeps you in shape then that can't hurt your self defense skills. But if you're specifically wanting to enhance your self defense skills you might as well do something more practical. If coordination for firearms training is what you're looking for, I think you would be better served by something more fluid, like gymnastics or dance. Or perhaps kickboxing or taebo. Traditional martial arts are so static and blocky that they might be counterproductive. The sparring would help, though, so I would focus on that if you're already in a regimented martial art like Karate et al.
Just my opinion, and maybe some advice for anyone thinking about going down this road. I don't know where the OP is in all this, if he's just starting out or has been in it for a while.
ETA: In all those years, I must have taken dozens of tests, between stripes and belts. Oh good grief, I forgot all about the stripes! That is the scam of all scams. Some schools even have different levels of stripes, where narrow ones turn into wide ones, so you're looking at five tests in total to advance to the next belt. Anyways, what I wanted to say is never, not once, did anyone ever fail a test. I've had four schools and dabbled with a fifth, so you would think out of all those tests, people, and schools
someone would fail. And I have seen people fail parts of the test that were supposed to be all sacred, must do tasks to pass; but the "board" (the senior black belts)
always passed them. It's an interesting racket. You can't test until the master says you can, and when you do you just cough up your 70 bucks and you're guaranteed advancement. It's not about gauging your actual abilities, it's about stringing you along. They know most people quit at black belt, so they want to keep you paying the monthly dojo fees for as long as possible, but then again they can't let you get bored. It's all about juicing each and every student for as much as they're worth. They see some students obviously won't stick with it for long, so they test them rapidly to get as much out of them as possible before they get bored and stop coming. The true believers on the other hand, who will make it to black, they want to slow down so they get those dojo fees. The bottom line, if you were learning anything useful then people would be failing the tests left and right. It's like being in a math class where everyone gets an A. You know good and well no one can be learning anything.
P.P.S. Oh no, I forgot about the student teaching! It's all coming back to me now lol. When you get into the higher belts you're always required to start teaching, so half the time you spend teaching forms to lower belts instead of learning new stuff yourself. And no, you do not get paid, or even get a discount on dojo fees or testing or pro shop or anything. It's a "tradition," so you have to do it. Funny how all of these "traditions" are 100% financially motivated eh?
But yea, your typical class as a higher belt is you show up and first you run the warmup. Then the master comes in and assigns tasks to everyone. You spend the first half hour teaching forms to the lower belts. Then after that the master takes you into another room to teach you something new while the lower belts practice what you have taught them. So you're paying full price and getting half the instruction time. I had totally forgotten about that.