Glock 42 in .380: the smallest slimline explained
The Glock 42 is the smallest pistol Glock makes, a .380 ACP single-stack introduced in 2014 that is a little smaller and lighter than the 9mm 43 and a good deal softer to shoot. It is also the pistol people argue about: the 9mm crowd asks why anyone would carry a .380 in a pistol nearly the size of a 43, and the 42's owners answer that it is the pistol they actually carry every day. This guide covers the pistol, the cartridge, the ammunition it likes, the magazines and sights, and who it suits.
The pistol
The 42 has a 3.25 inch barrel, is 5.94 inches long, 4.13 inches tall and 0.98 inches wide, and weighs about 13.8 ounces unloaded. The magazine holds 6 rounds of .380. It is a locked-breech pistol, unlike most pocket .380s that use a blowback action, and that is why it is softer to shoot and easier to rack than the smaller .380s it competes with. The trigger, the takedown and the controls are the Glock pattern in miniature.
Size against the 43
The 43 is a third of an inch longer, a tenth of an inch taller and a twelfth of an inch wider, and it weighs about four ounces more. Side by side the difference is small; in a pocket or on an ankle, it is the difference between a pistol that goes and a pistol that stays home. The 43 shoots a full-power 9mm from that size and kicks accordingly; the 42 shoots a .380 and does not. People with smaller or weaker hands, or a wrist that objects to a 9mm subcompact, often shoot the 42 better than the 43.
The cartridge
The .380 ACP is a 9mm bullet in a shorter, lower-pressure case, with roughly two-thirds the energy of a 9mm. From a 3.25 inch barrel, most 90 to 100 grain loads leave at 850 to 1,000 feet per second. The argument against it is penetration: a .380 hollow point that expands fully may stop short of the depth the FBI protocol asks for. The current answer from the ammunition makers is a load designed for the cartridge, either a bonded or controlled-expansion hollow point that expands modestly and penetrates, or a solid copper design that does the same. The old advice to carry ball ammunition in a .380 is out of date; the new loads are better.
Ammunition that works
For carry: a hollow point marketed for short-barreled .380s from a major maker, tested through your pistol for at least 100 rounds. For practice: 95 grain full metal jacket. The 42 is more particular than the 9mm slimlines about ammunition, especially with light loads and with some flat-nosed bullets, so the test matters more here than on a 43X. Once you have found a load that runs, buy it in quantity and do not change it without testing again.
Magazines
The 42 uses its own 6-round magazine, with a flat floorplate and an extended floorplate that gives the little finger a rest without adding capacity. Aftermarket +1 and +2 extensions exist and work when tested. Nothing else fits it, and its magazines fit nothing else. Three magazines is the right number: one in the pistol, one spare, one in rotation.
Sights
The 42 ships with polymer sights in the slimline dovetail, the same pattern as the 43, 43X and 48, so any slimline sight fits. A steel night sight set is the most common first upgrade, since the factory sights are hard to see and easy to break. There is no MOS version of the 42; a dot means a milled slide or a dovetail-mounted micro dot.
Holsters
The 42 is the one Glock that pocket carries well, in a pocket holster that covers the trigger and stays in the pocket on the draw. It also carries in an appendix or strong-side Kydex holster like any other pistol, and on the ankle for those who sit all day. Holsters for the 43 do not fit it. The carry setup guide covers the positions.
Shooting it well
A 42 is easy to shoot and easy to shoot badly, because it is light enough that a heavy trigger finger moves the whole pistol. Grip it high with both hands, press the trigger straight back, and practice at 7 yards until the groups tighten before moving to 15. The short sight radius punishes a sloppy sight picture; a bright front sight helps more on this pistol than on any other slimline. Fifty rounds a month keeps the skill.
Maintenance
The 42 is a Glock and cleans like one: field strip, wipe, brush the bore, a drop of oil at the rails and barrel, striker channel dry. A small pistol carried in a pocket collects lint faster than a belt gun, so it gets wiped weekly. The recoil spring assembly is small and works hard; replace it every few thousand rounds.
Who it suits
- Someone who will carry a 42 every day and would leave a 43 at home.
- Someone with hands or wrists that make a subcompact 9mm unpleasant.
- Someone who wants a pocket or ankle pistol as a backup to a bigger gun.
- Not someone choosing a single primary pistol who can carry a 43X or 48 comfortably; the 9mm is the better cartridge when the size is not the deciding factor.
Compare it with its bigger siblings in the slimline comparison, and see its magazine options in the magazine guide. Browse Glock 42 pistols and parts and .380 ammunition; the pistol ships to your FFL dealer, everything else to your door.
General information, not legal advice. Current as of September 2026. Laws change; check the official source before you act.
