The Glock 19, in 9mm is one of the most carried pistols in the world. The magazines it comes with, standard, is 15 round capacity. Weighs a couple of pounds. Outside the belt at 3-30 Kydex holster. Under a Florida shirt.
A couple of must-have essentials are required add ons. First steel night sights. Glock factory-approved extended slide lock (release) manufactured by Glock.
With a little polishing of internal parts, my trigger weight is 4.5 lbs. Still not a perfect trigger, this is not a Colt 1911. Not essential, but makes for smoother magazine changes, on my Gen 4 the mag plug, flush fitting.
The Gen 4 model, when it was released, was a disaster! Introduced on this model, the dual encapsulated mainspring. It took months to make it work, now perfect. I have shot thousands of rounds of factory ammunition in IDPA matches, with one problem round. A factory round, a dud! Not the fault of the gun. Drove the 115g projectile halfway down the barrel.
The other side of the belt, a G17 spare magazine, and an incredible flashlight, a Surefire. The light sees more use than the pistol or the spare Mag!