The Glock 21 is a great pistol, but its also a great big pistol. I have one myself I carry as a sidearm in black bear territory. The G21 has a pretty chunky slide, and the grip goes around a magazine double stacked with 13 rounds of 45. Its not really meant to be hidden or even carried discreetly. its meant to be in a duty holster on the belt of a police officer or a military service member, along with all the other stuff these people carry on a duty/war belt. Also, 14 rounds of 45 weighs exactly twice as much as 7 rounds of 45- considerable gross weight in ammo when you consider they are usually 230 grains of projectile (exactly twice the dead weight if they were 9mm rounds- typically 115 grain projectiles). If you are wanting a Glock 45 for concealed carry, the G36 (single stack 45) is actually meant for this task, but you get no increased rounds from your 1911. The Glock 30 is 10 rounds (I think) but has the fatter grip, just not as "long" as a 21.