Image via WikipediaThe debate on high-capacity magazine for a handgun reignited after the Tucson shooting of 2011, when a Congresswoman was shot through the head and six others died, and over a dozen more injured. The shooter used a Glock 19 with a 33-round high-capacity magazine. He had at least one more but he didn't get a chance to use it.
Keep in mind that a normal Glock 19, a compact version of Glock 17, has a 15 round magazine (with 9x19mm parabellum rounds). So 33 round mag is more than twice the capacity.
Real shooters disdain hi-cap mags because:
1) they disturbs the balance of the gun.
In general, you want the gun to be FRONT heavy, to help you control the tendency for the gun to "nose up" after a shot due to the way barrel is located relative to the arm. A hi-cap mag adds more weight to the REAR of the gun.
2) they are far less reliable
US military tested in 2004 their version of hi-cap mag, called C-mags, for their M-4's / M-16's, and found them to be unreliable.
The reason is simple: the spring inside does NOT give constant pressure. By the time you got down to last few rounds the pressure exerted is far less, but if you load it all the way down it may just feed too hard and cause a jam. In fact, most shooters even underload normal factory mags by a round or two to make sure they can feed properly when used.
3) hi-cap mags serve no legitimate purpose other than to engage high number of targets with minimal training
A pistol is a short-range weapon (25-50 yards effective range, probably even less). If you have THAT many enemies that close, that requires 33 round mags, you are already ****ed, gun not withstanding.
Besides, real shooters, can drop mag, reload, and restart shooting in less than a second. They don't need hi-cap mags. If they don't have time to reload, they usually use a second gun, i.e. a "backup piece" instead. Or else they pack something better, like a submachine gun.
The only conceivable reason to have high-cap mags are, to me
1) Someone wants to prove he has a bigger gun than _____
2) Someone plans to shoot a LOT of targets with minimal training.
And that is what happened in Tucson: someone decided to shoot a lot of targets with minimal training.
Real trained shooters don't need or even WANT hi-cap mags. There are no legitimate use for them. Thus, they should be banned. And they WERE banned, until the "Assault Weapon Ban" expired in 2004.