Hollow and soft points work quite well but stay away from the lighter varmint loads. Frangible might be a better choice. The AR has good ergonomics and breaks down easily but I was not trained on them. M1 Carbine, yes I am that old. I prefer the Mini 30. Do not over look a good AK 47. Not a fan of DI. My preference in the house is a 9mm carbine. The Keltec Sub 2000 to be specific which is available with Sig 226 mags if that is your preference. Mine takes Glock. The Ruger PCC carbine is very good but overweight. The Keltec is 2 happy sticks (33 round mags) lighter and only 30" with a flash can attached. Folds to 16". My wife keeps a Ruger 10-22 and a Glock 44. It is what she can handle.
Do not overlook smoothbore. I keep a 410 shotgun with 9 pellet #4 buck backed up with 4 pellet 000. Light recoil, lower noise level and usable by smaller shooters. There is also a 12 gauge loaded with 27 pellet #4 buck in the safe if I need heavier firepower like Antifa outside. Hard to take out a Molotov Cocktail with an AR. For 12 gauge indoors I would look at Minishells which will almost double your mag tube capacity while reducing recoil. 7 #4 buck and 4 #1 buck in each round. Do need an Opsol adapter at least for the Mossberg 500 or 590. 00 buck has a lot of over penetration. #4 buck will penetrate walls but not as badly as 00. Not a fan but for close range, 5 yards or less, #4 lead shot is viable.
Going through various blogs and videos, a 77grain Sierra Match King Open Tip Match Boat Tail, MK262 round from Black Hills, IMI, or others may be the ammunition youâre looking for in a home defense application. Home Defense 5.56mm Ammo: IMI's Mk 262 Clone 77gr OTM gel test - YouTube
Theyâre expensive (2x - 3x) compared to other AR platform ammunition, but theyâre not for plinking at the range. Avoid M855 for your home defense rounds, but bottom line use what you have to stop the immediate threat(s).
@Al1 You may want to look at PWS. They look and act like an AR but are designed similarly to the AK with the long stroke piston. Supposedly can go a long time without cleaning though I havenât tried. Only problem is finding one. Took me over six months of waiting lists, back orders and late night searches.
Good stuff
Iâd be interested in buying one day. Expensive but would take away over penetration legalities.
I like mine with a 16 barrel. Easier to maneuver through the house.
Mine is 7.5 inch barrel 300AAC BLACKOUT, a lot easier to maneuver around the house.
I built it for my wife.
There are many hunting loads offered in 223 with everything from HP to SP to ballistic tip. Go to https://www.federalpremium.com/rifle/ and use their filters to see one manufacturers variety.
BTW, I recommend a 10.5" to 11.5" barrel AR pistol for home defense (Ruger 556 is nice). Very easy to maneuver and mine is very accurate and not noticeably louder than a 16" carbine. What I have found to make any rifle loud to the shooter and partners are muzzle brakes. They are absurd on 5.56 / 223 though many people use them to the detriment of all at the range.
If this weapon is solely/ primarily for home defense you can get a 7.5" barrel for .223/5.56. I am usually strongly against them because they get no where near the velocity those light bullets need. But it does minimize over penetration.
You will definitely want a flash can though. Blinding yourself is no good.
My 10.3" SHTF truck gun has 1 mag of frangible in the well, & one of green tip coupled to that. Mobs on foot or coming from a vehicle, Iâm ready.
Alternatives to the AR-15 would be an SKS/AK-oid, or Mini-14(or Mini-30)
Or get a shotgun
Right now finding ammo is the issue.
Just get a 1911 and call it good. The newer ones shoot hollow points very nicely.
I am a 30-year Navy veteran, so we served in the same branch of service. Although, my buddy, a former USMC Gunnery Sergeant would say that even though the USMC is part of the Navy, itâs the âMenâs Clubâ portion! I agree! Kidding aside, thank you for you service to our great Nation.
As far as weapons goâŠget an AR-15 because you need a long gun. I, too trained on an Mâ16, when the Navy guys were allowed to handle small arms! They are similar in many ways and, once you shoot one, it will seem like an âold friendâ. I also suggest a 1911 .45 caliber. That is old school, before they issued 9mm. Great to have both, for various reasons. As they say, âYou can never have too many guns!â
@Vincent41 Welcome to the community. I like your choice of âold friendâ calibers 
Stay safe, Bruce and Nancy.
I have an AR-15 and like it. But, because of the speed of the bullet, over penetration can be an issue even with hollow-points. A 12 gauge pump shotgun with OO buckshot is by my bed and will stop anyone. Over penetration is much less of an issue with the shotgun. I have a 9mm pistol on my stand as a backup and my AR-15 comes out if all else fails. Doubtful. 
Buy 308 or 410 if you have to choose one
Semper Fi Marine. I enlisted in the Army in '70 and also have experience with the M14 and M16, among others. As a citizen of a free country, I also purchased a scary black rifle, âbecause I couldâ. Just as now there was much talk about reinstituting the âAssault Weaponsâ ban, which most of us know was a ruse to eventual confiscation, which is why I made my purchase. A government announcing its plan to confiscate civilian firearms will encourage law abiding citizens to exercise their rights to the extreme.
Whatever you choose to do, it will no doubt be a good choice.
All the tests I have seen show 00 buck over penetrating much more than most .223 ammo. Some 9mm will even penetrate more than many .223 rounds. The high velocity of .223 often causes it to fragment after it hits objects. With the right rounds .223 can have a very low risk of over penetrating. Though a 9mm handgun is my go to inside the home defense gun for a variety of reasons.
Edit to add- I am not a shotgun guy but my understanding is that #1 buck is a good option for inside the home defense as it gives adequate penetration with less chance of over penetration. But it seems hard to find compared to 00 and the often sub marginally penetrating #4 buck.
Besides the regular posters did anyone read the link I put in post #3 ?
It has real world testing of shotgun, pistol, and rifle penetration thru interior and exterior house walls. Spoiler alert, with proper ammo selection 223/556 is stopped by a normal sheetrock interior wall. The biggest problem is finding that ammo in stock today. Secondary problem is it is loud.
I agreeâit is secondary. I canât imagine myself worrying about my hearing in a life-threatening situation.
I have an IWI Tavor X95 in 9mm. It is much shorter than an AR 15 but still has a 16.5 inch barrel. Mags are 32 round in the Colt SMG format. Recoil is light. Recoil thrust vector is straight into the shoulder, so very little muzzle flip. With my can on the front and 147 grain ammo, I can shoot as long as I like with no ear protection, but most of the time, I wear it anyway. In rapid fire, it is not difficult to put 30 rounds into a 4 inch circle at 25 yd using Meprolight Tru-dot sight. With 9mm Nato ammo, I can consistently ring a 12 inch plate at 200 yd. I am a real fan of the piece.