A good reason that even if you are a lefty, or as I so shoot long guns left handed because of my eyes, stick to right handed ARs. Lefty AR uppers require lefty BCGs. Not an easy thing to find easily. Sure, they are online, but every AR part vendor out there carries standard BCGs.
I'm guilty of knowing I should have extra parts kits for my ARs. At least an extra spring and pin kit, plus and extra bolt. But, I don't. Yet.
I've also been wondering just how well it would play into reality if things really went so totally south just how more burden than asset having a lot of guns and rooms of ammo would really be. Unless you have impenetrable, serious fire resistant bunkers and ways to get in and out securely, just how much of your stocks could you get out of a house that caught on fire? First reaction would be to try and put it out. By the time you realize you have to abandon the place you have used your minimal time in which you could try to move guns and ammo out.
A lot of us here seem to be realistic in that we are bug in, not out people. However, if the situation came up that you really need to unass the AO how much guns, ammo, gear, not to mention food, meds, and essentials could you load out? Both in terms of speed and space for. What do you do with the stuff you leave behind? Blow it all in place so no-one else can get it or hope you can come back and get back before anyone else gets in?
Having a select kit with quick grab mags/ammo is probably a good idea.
I'm still thinking about mine. Naturally, one of the ARs. Possibly hand the one with the optic to the wife and run my dissipator with carry handle and light. On the handgun front it's a toss up. I have a lot more .45 ACP JHP that I do 9mm JHP. So one thought is toss in the Glock 30s and the Glock 21. That's in a Bianchi UM holster ready to go. I have something like 9 mags or so for the 21 and 5 for the 30s.
On the other hand, I have a Beretta M9A1 (bedside gun) and a M9. I also have something like 18 standard Beretta mags, plus three sticks mags. I also have the PAK-9 AK type pistol that takes Beretta mags, or I can swap the magwell to take Glock mags and I have a few Glock 17 and 19 Mags. Unfortunately while I have plenty of 9mm ammo, it's almost all FMJ in 115 and 124 grain.
On the shotgun front having the 20"/7+1 Mossberg 500 would be nice, however the Shockwave would be something that would be slung over the back easier and still be able to use the AR for general use. It would also pack easier. Toss the Shockwave and PAK-9 in a tub or pack with some ammo in a vehicle or even on the packs of you and another for use later after you settle in somewhere.
The hardest decision would probably be between the pistols. Something to be said for both.
If I wasn't too concerned with having to face down the hordes, just get by with less for a while that's different. I'd keep my Rossi M92 Trapper in .38/357 Mag and as much as I like the M65-1 I have, I'd probably opt to keep the S&W 686 Plus. Maybe the M65 as it's a 4" and the 686 is a 6". I have a fairly decent stash of .357 Mag JHP, and maybe a box or two of SP ammo. I also have dies, powder, bullets, and primers for that caliber as well.
Also keep at least one .22 LR and possibly the only .22 pistol I have. A Ruger Mark II Bull Barrel.