i am not an expert on firearms, though i have read pretty thoroughly on the subject (including some who are indeed, expert), and though i have pursued various aspects of the shooting sports, for a good long while. but, i like to ruminate and think about things, and i think i have a few pertinent comments you may find helpful.--
in case you are thinking about buying a gun to protect your person and property, you family, that sort of thing. and, in case you are thinking that you may have recourse to one (or several) to protect your liberty, and your ancient right.
that sort of thing.--
first off, if you lack experience in such matters, keep it simple. your skill levels do not excuse buying exotic or overly complicated weapons and systems. you are not going to become a 1500 yard sniping machine by purchasing those abilities.
simple means simple.--
shotgun. a 20 gauge pump action shotgun, and you can do far worse than a mossberg model 500, or a remington model 870. a shotgun, as short coupled as you can get it within legal restrictions, such that it can be handled and brought to bear in the home. you probably won't carry a shotgun outside the home, under your trench coat.
pistol or revolver. i favor the colt 1911 type semi-auto pistol, but i did not come to even rudimentary skill levels with it for a long, long time, nor did i get used to the level of noise and recoil that a pistol makes even with sound attenuation, such as muffs or plugs.
and, neither will you. pistols take practice, to learn how to shoot, and to learn how to handle in a safe manner. if you have to take a handgun up in protection of yourself and others, the first thing you don't want to hear from your lips is, "gee, i wonder what this hickey does."
buy a revolver, and a single action hog leg like in the western t.v. shows such as a colt peacemaker, is just as serviceable now in your own protection as it was in the 1870's, and they are butt wipe simple to run. now, they shoot where you point them, and if you don't familiarize yourself with a gun and practice with it, and learn how to hit with it, you simply are not gonna hit what you intend to hit.
unless you are willing to put the time, practice and money into shooting a pistol, any pistol, don't buy it.
i would suggest a handgun in .38 special, as it is ridiculously easy to shoot compared to bigger calibers, yet it is sufficiently lethal and unpleasant to be shot with so as to discourage all but the most determined of aggressors. bad guys have been killed with the .38 special fora long time.
which brings us to rifles. were i you i would start with a small-ish bolt action rifle, in a relatively mild mannered cartridge. since you are not hunting elephant, or critters they weigh on truck scales, you do not need a .458 winchester magnum as a starter weapon. nor do you need a rifle that weighs 9 or 10 lbs. with a 26 inch barrel.
ruger, winchester, remington make small-ish bolt actions which have a simple manual at arms if you will, and just a bit of fiddily and handling reveal their methods of operation. mossberg also makes a nice compact weapon, which has freely borrowed the good parts of gun making from the last 50 or 60 years, having some winchester here, and some remington there, and some savage in other places ... in short, they copied the good stuff and stayed away from the confusing parts.
buy a caliber/cartridge which you can learn to shoot relatively easily. with store bought ammunition. with just plain old bullets, no new fangled expensive stuff that will shoot 9 miles and hit a postage stamp. i would suggest something along the line of the .250 savage ... it will bark a bit, but it won't bite you.
and, you can learn the basics by reading or watching utube. but as joe willy namath said with regard to his romancing skills, practice, practice, practice.
do not buy an ar-15 as a beginners rifle. i do not care what the asshole behind the counter trying to sell you on the virtues of the ar-15 says. it is too damned persnickety in its function to try to learn how to shoot on. stay away from the .308 winchester, even if the salesman says, oh, it's a real easy shooter. bull shit!! it is loud. it kicks. and, it is not the place to start.
i won't go into the details. btw, i own more than one ar-15. but, i am a glutton for punishment, and i learned the hard way.
but, if you simply have to have an "assault rifle." then go with the a-team, and buy a ruger mini 14, or a mini 30. i am not advocating that, but, if you go with an idiot's choice in the matter, i regard it as the least of all possible evils in the semi-auto scheme of things.
and, it goes with what i have been saying.
it is a rifle, and you can aim a rifle and hit with it, far easier than any other kind of gun. and, it only shoots small cartridges, e.g. calibers, such as the .223, the 7.62x39mm (model 43), and the 6.8mm remington spc cartridge. (if you don't understand that gobbledygook, then i have proved my point and you should stick with a small bolt action.)
as an added bonus, you can see most of the innards of a mini-14 right out in the open, and the way it operates is pretty easy to comprehend. keeping in mind of course, that so is chess, and so is "checkers." (i once went to visit a friend in boise, idaho and the family of the object of my attentions, thought it would be fun if i played with "grandpa," who acted like he was a bit potty. well, he waxed my butt about 20 times, and toward the end he began to cackle with each move. everybody had a good time.)
and, if you seriously insist on being able to hit what you are shooting at. it should give you ample pause in all of this to understand that people have been trying to figure out how to aim a pistol/revolver/rifle for centuries and no one method really solves all the issues involved. it is hard to do, given that your eyeballs and perceptual apparatus really only focuses on one thing at a time, more or less. with a "sighted" weapon you have rear sights, front sights and the object you are trying to hit .... that is three things to focus on, and it cannot be done. red dot sights/eotechs, aimpoints and the like. buy whatever you buy, and then buy a "red dot" sight to put on it, preferably one that you don't have to line up exactly plumb to use. there will be an image (unless you close your eyes), and a dot, and you put the dot on what you want to shoot. it is that simple.
(oh, yeah, you have to load the gun, chamber the round, aim and pull the trigger.)
simple, remember simple. red dot sights simply make life simpler.
well, that is it. i have expended 1200 words on "simple." simply because i needed to.
john jay @ 08.23.2020
p.s. and, finally. join the n.r.a., find an n.r.a. shooting range in your area, and then go there and take instruction from an n.r.a. certified instructor. you should be willing to pay for this, as a necessary part of learning how to shoot.
and, in learning how to store your weapons and ammunition, how to keep your kids out of it, and how to access it when you need them. and, pay attention.
and, oh, yeah, .... have fun!!!!