Shield Arms Magazines & Accessories

Shield Arms is a Montana-based firearms accessories manufacturer that built its reputation almost entirely on one idea: fit more rounds into a Glock 43X without making the gun any bigger. That sounds straightforward. Executing it well enough that the product sells out regularly and earns genuine loyalty from serious shooters is a different matter entirely. They are probably best known for their S15 pistol magazines for the Glock 43X and 48, which boost the pistol’s capacity from 10 rounds to 15.

Brand Story

Shield Arms was founded in 2017 in Bigfork, Montana by Brandon Zeider and Seth Berglee with the goal of providing innovation and value to the firearms industry. The company began in Zeider’s garage and expanded twice in its first four years. Zeider had spent years covering the firearms industry as a blog writer before meeting Berglee while attending a shooting class. Berglee, who attended Ohio State on a shooting scholarship before joining the army, was teaching the class where the two met. Their first major commercial breakthrough came directly from the Glock 43X platform. The S15 magazine, which carries 15 rounds instead of the usual 10, caused demand that drove yet another expansion.

Shield Arms is no longer a garage operation. Rows of CNC machines now produce components held to tight tolerances. Every product is manufactured in the United States, keeping complete quality control over the production process. They stand behind their work with lifetime warranties because they believe in building products that last.

Product Lineup

S15 Magazines for Glock 43X and 48

The S15 is the product that started everything. The patented S15 Gen 3 is a flush-fitting 15-round steel magazine for the Glock 43X and 48, providing 50% more capacity than OEM 10-round magazines. It sits flush with the grip. The pistol looks and carries exactly as it did from the factory. The only thing that changes is how many rounds you have before a reload. The increased capacity comes from patent-pending magazine geometry that allows rounds to stagger, fitting more into the same amount of space. The Z9 covers Glock 43 owners: the Z9 is a 9-round steel magazine for the Glock 43 that provides 50% more capacity than OEM in the same footprint as a standard magazine with pinky extension.

Magazine Extensions

For shooters who want more than the flush-fit option, the extension lineup gives you real flexibility. The +5 extension adds 5 rounds to an S15 magazine for a total of 20 rounds. The +10 extension delivers 25-round capacity for the Glock 43X and 48. The +2 extension increases capacity to 17+1 and is machined from billet aluminum. These are practical tools for competition, range training, and home defence. Every extension is machined aluminium, not cast or injection-moulded, so they hold up.

Steel Magazine Catches

This is a detail that matters more than most people realise. The premium steel mag catch for S15 magazines features enhanced ergonomics with extended knurling, beveled edges for smooth reloads, and increased magazine engagement. The steel construction is necessary: the heavier S15 magazine body puts more load on the catch during drops and reloads than the factory polymer part is designed to handle. Swapping to steel here is not optional if you’re running S15 magazines and want reliable retention.

Magwells

The carry magwell is an ultra-low profile design specifically for the Glock 43X and 48, CNC-machined from aluminium with a hard anodized finish, rounded no-snag edges for comfortable all-day carry including AIWB, and improved reload speed without compromising concealability. Drop-in installation with included hardware and compatibility with S15 magazines, OEM Glock magazines, and Shield Arms extensions. It does the job without adding bulk you can feel on your hip.

Why We Stock Shield Arms

At No Boring Guns, we carry Shield Arms because our customers ask for it by name. The Glock 43X is one of the most widely owned carry pistols in Europe, and demand for capacity upgrades on that platform is consistent and growing. Having a reliable European source for these accessories matters because shipping direct from the US adds cost, import delays, and warranty complications that most buyers want to avoid.