Here's my $0.02
I see it as 2 specific types of shooting requirements. Many people think they need a "sniper" rifle, when that is not what they really would want.
There's what you might call a "sniper rifle" and then what you might call a "designated marksman" type rifle.
This is somewhat from a SHTF perspective, but a bolt-action scoped rifle isn't useful for engaging multiple targets rapidly. Not as well as a semi-automatic scoped rifle. I guess it depends on what you want to accomplish. A bolt gun is more of a 1-shot 1-kill type weapon. That assumes your on OFFENSE. Not reacting in a defensive situation. Such a platform is the tool of a predator. It would be used to eliminate high-value targets.
I prefer a semi-automatic, military patterned, scoped rifle instead. This allows me to deliver lead at a much more rapid pace to engage many more targets quickly. These rifles have enough accuracy, ie "minute of man" accuracy out to several hundred yards, which in a battle or SHTF, is all you need. Such a scenario would better call for accurate rapid fire.
If I wanted a tool to get rid of undesirables in some tyrannical world, the best choice would be break action rifle, like an NEF, sawed down, in some caliber like 308. It would preserve its velocity due to having a longer barrel in a shorter platform (since it has no action). It is marginally slower than a bolt-gun, but it doesn't matter, the name of the game is SHOOT then SCOOT. Make your shot, and leave. Small, light, compact. Get a nice optic on there, like an illuminated range finding reticle...and you've got a great tool to take out the trash out to pretty long ranges.
It isn't likely that one will be in a ghuille suit stalking for days in brush to seek out some high-value target for assassination. More than likely, it will be you in a car, rolling down a window and popping the badguys from 100-300 yards, then driving off. Just like in Iraq right now. Mix in with the people in an urban setting. Not even our elite snipers can possibly stop this, it would require that every single part of society be surveilled constantly. This is impossible. If you actually think you can go toe-to-toe with any real snipers in a rural setting - you're dead meat. You will be going up against a much more highly trained, professional sniper, with far superior equipment. We're talking thermal detection, superior night vision etc...Bubba is going to be the equivalent of a prairie dog waiting to be shot.
A long barrled AR-15, or an M1A, both scoped would be great platforms. Lower recoil than highpowered bolt action 30 cals, easier to deliver more lethality. Very good for social situations.
