AR-15s
No matter what you get, if you do not go out and shoot it regularly, it won't matter. Anything you do if you want to do it well requires putting in your time, Body building, bowling, shooting pool, shooting, reaction times, and on and on. It doesn't come free. Commitment.
Most weapon malfunctions are not part related. Owner maintenance, shooting technique.
The most problem firearm component would be magazines. Get the best quality you can find, protect them from damage, especially the feedlips,
Get a progressive loader so you ca n afford to feed it. Do not store powder, primers in a security safe. Powder should be stored in a proper container. It needs to be vented. Expanding gases in a confined area = explosion instead of just a burn.
Shotgun ammo for the home. Not buckshot. You are dealing with distances less than 20 feet. 1 oz. of #8 shot carries the same energy as 1 oz of buckshot.
Difference is buckshot pellets individually carry more energy which means they will penetrate more per pellet. Not wanted in the home. A miss is 90% more likely than a hit regardless of what you may think. You don not want projectiles going through walls etc.. where others may be hiding or in another room. Maybe your family members.
Shotguns do not pattern in real life like they do in the movies. Even a sawed off barrel will not pattern larger than your fist inside a house.
Always follow the basic firearm safety rules. Every gun is loaded, always keep your finger off the trigger until ready to fire. Never have the muzzle pointed in a direction that you don't want to fire at. Never shoot to wound. There are no such things as accidents. Only carelessness, lack of concentration.
Join a gun club, support 2nd amendment political candidates. Be aggressive if you want to keep your rights.
Take your kids shooting, attend a hunter safety course, take gun safe handling classes. Be aware of your surroundings.