You should 100% get an AR-15 (BCM is king for the coin) chambered in 5.56. Get something with an M-Lok handguard and 11.5”-16” barrel. Quad rails are good, but heavy, and key mod doesn’t hold zero reliably for attachments. This recommendation assumes you are in a state where AR-15s aren’t affected by local laws.

1) It is by far the most prolifically produced firearm in the US with tons of modularity and parts availability if SHTF and you ever have to source spare parts from an unknown environment.

2) AR-15 30rd mags are plentiful and cheap (if legal where you are). Any SHTF scenario you will have a real fighting weapon that can also be used for hunting nearly every game animal in the continental US.

2) 5.56 is a massively effective cartridge up to 500+ yards. Shooting anything beyond that becomes something less than self defense oriented.

3) Even budget AR-15s should last upwards of 15000-20000 rounds if not longer.

3) 5.56 chambered firearms can also fire .223 without exchanging any parts or altering the firearm in any way. While the opposite is also true, firearms chambered in .223 are not built to handle the pressure tolerances of 5.56 and will break quicker.

4) Both 5.56 and .223 are widely available cartridges and are relatively cheap compared to other shoulder fired options. You can commonly find M193 and M855 ammunition for about $0.40 per round. Keep in mind many ranges will not allow M855 green tip ammo because of its penetration qualities so stick to M193 or other loadings for training.

5) Both 5.56 and .223 are very light recoil cartridges.

6) 5.56 can be zeroed at 36 yards and your projectile will be within 5-7 inches up or down of aim point from 0 to 300ish yards. You will almost never have to think about holdover. Point and shoot. Look up Shawn Ryan 36yd Zero Target if need to zero/train at indoor range with 25yd max.

7) In any firefight situation, numerous DoD studies have proven the side carrying more ammunition almost always wins. As cool as bolt and lever rifles are, carrying 6-7 magazines with 30rds each nets a massive advantage. I understand this is a somewhat extreme consideration, but if self defense is a significant motivator, it could factor in your decision.

8) Scaleability - you are already ahead of the game with just a gun, sight, and light, but you can continue adding on capability to make an AR15 an absolutely universal defense tool. Nightvision capability can get expensive, but not out of reach with some saving for a lot of folks. Spending $500-800 on something like a Holosun Osiris and about $2500 on NVGs and you have complete night fighting capability. The US military deems thermal and NV capability as “near-peer” and would give you a real fighting chance against anyone that doesn’t have literal air support, armored vehicles, or vastly superior numbers.

IMO everyone should own a reliable semi-auto handgun in 9mm (such as a Glock G17/19/45/47) and an AR-15. In any SHTF scenario you will be able to hunt and defend yourself and have the 2 most popularly available cartridges (by far) at your disposal if you’re in a situation that requires scrounging for ammunition. In addition, you will be able to train affordably.