Read this reply at:
http://www.thehighroad.org/showthread.p ... post484476
A guy named Zak Smith stated this:
Loading a shotgun is super-slow
One thing to consider is that it takes a heck of a long time to load rounds into a shotgun when compared to the load time for a semi-auto rifle or pistol.
For a pistol, it takes approximately 1.2 seconds to change mags (if you've practiced a bit).
For an AR-15, it takes a little bit more than that - maybe two seconds.
In those two weapons, you start off with between 9 (e.g. a 1911 with 8+1) and 31 rounds available, and reloading is fairly rare.
For a shotgun, to load a single shell takes about two seconds for someone of average ability. The best shotgun shooters in 3gun load faster than one shell per second. I think I currently at about 1.6 seconds per shell (load 3 at once). Fumbling a reload is much easier with shells vs. reloading a pistol magazine, and you have an opportunity to fumble each shell, not just per mag.
So it will take an average person 6-10 seconds to load four shotshells into a shotgun - assuming it hasn't been run dry - and they have the opportunity to fumble each of those four shells.
That is one important reason capacity is important in a shotgun.
In 3Gun, shotgun capacity is important because if you plan to load only as many as you need to shoot, and then shoot (and reload) to that plan, every round you can have in the gun at the start buzzer instead of loading later will knock a full 1-2 seconds off your time.
