nikto

if you really thought about needing a second shot, you'd own an autorifle, not a bolt action. If the single shot is built as a rifle (not as a shotgun with a rifle barrel) it could be made to have a decent trigger pull, and cost a LOT less than a bolt action. it's the huge mainspring, necessary to pop a shotgun primer, which makes the H and R type of single shot have such a crappy trigger pull.

Terry G

Bolt actions like the Browning
X Bolt can be manipulated easily for the second or third shot. Many Hunters prefer them. They also come in larger calibers for the very largest of game. The .223 that you expound on is NOT suitable for everything just because it has "soft" recoil. If your after large game you have man up and deal with recoil.

Garand

I have a very nice Shilo-Sharps #3 Sporting Rifle in .45-70, as well as various bolt action rifles. Flexibility & versatility!

gripper

I prefer autoloaders for general utility. That said, I'd NOT feel incapable or terribly bad off running a good bolt action beyond 400-500. As far as that " general utility thing goes,what you have when you need it -and the practice/skill/muscle memory that goes into that are not-and should not-be mutually exclusive.
Thankfully, my eyes are still good, and despite many old injuries; I have no issues moving out/lifting/carrying/stabilizing etc.
Make no mistake: I prefer " medium-large caliber ", but the 5.56 is very efficient and if you work with anything all the time, you'll not only know it's limits;but be able to stretch them.
At closer ranges ,a lot of M193 ball can out penetrate M855/SS109 and heavier. It's beyond the closer ranges they do better on barriers/protective gear. Once you get beyond the case capacity/volume/bullet weight & density below 6.5,that's where (at longer ranges-for some iron sights, others glassware) the larger caliber stuff will do better. Both accuracy and barrier wise.
Perfect world? Work with both. Most of us do what we can WHEN we can.

nikto

but when there's no evac, no safe base and enemies will be everywhere, 24-7, there is no KNOWING that they are 400+. Enemies can easily pop up at 50m, at night or early in the morning, having changed during the night. it's just a fantasy that you can know, and the bolt action is ALWAYS a horrible handicap if you need a fast second shot. There's no reason to own one anymore, now that the Ar's are sub 3" at 300 yds, plenty good enough for varmint hunting with superb triggers and much more ability to handle the heat of rapidfiring, without the mirage problem from the hot barrel, on prairie dog towns.

without the .22 unit, you're screwed on getting enough rapidfire practice (from either shoulder). Without the silencer, you're screwed (period) in a fight. It costs $100 or more to get that bolt action threaded, and you have to send it off for the job, too, seriously risking never seeing it again, and putting that serial number in your name (if it aint so already) Bolts mostly don't have iron sights anymore (if they've got a decent trigger pull) so you have to add those, and a see thru scope mount, and add luminous sights, or a very expensive night scope. gotta get over this idea that you'll get to switch guns as needed. you won't, if shtf. You're going to be stuck with whatever you started with, and whatever you can scrounge.

Garand