Here's a guy just screwing with an 1890's enfield, showing how fast he can shoot. More at: Bolt Action
The uninformed think that a bolt action hunting rifle would somehow dramatically decrease the death rates in a mass shooting. Two of our most famous mass shooters (Charles Whitman and the DC Sniper) both killed 17 people with one: which puts them on the high end of the mass shooting spectrum. (The average is around 5). And WWI killed plenty of people with them. A few guys with them could hold off hundreds. Even mass charges against a line of them didn't end well for most, and that's with smoke, grenades, and artillery support.
Pre-WWI the British and the Americans had training with their bolt action rifles, that included a mad minute: seeing how many holes you could put in a target at 300 yards using their bolt action rifles -- you had to do 15 to qualify, but the peak was about 38 shots per 1 minute. But that's 300 yards with a really powerful round (30-06), if you reduced the range and size of the round to something about 1/3rd the size (a .223) and you could easily up the rate of fire. The average mass shooting is like 15 minutes, do the math on that. Throw in that someone could have a backup gun (or two), and that you can speed-load these with clips/etc. The average death rate is one person every 3 minutes in a mass shooting event: people don't charge the shooter, they wait. A bolt action can kill as many as an assault rifle with those realities. Again, the problem is the guns action, it's the response times that matter.