S15 Magazine for Glock 43X/48

The Shield Arms S15 is a steel-body magazine that fits flush in the Glock 43X and 48 grip, increasing capacity from 10 rounds to 15 rounds with no external dimension changes. This is the single most popular upgrade for the 43X platform because it solves the gun's biggest limitation (capacity) without adding any bulk to the concealment profile.

The S15 uses a staggered double-stack to single-feed design in a steel body. The metal construction is both its advantage (thinner walls allow more rounds in the same space) and its primary concern: the steel magazine body wears the factory polymer magazine catch over time. Shield Arms sells a steel magazine catch (sold separately, ~$35) that is mandatory for long-term use. Running S15 magazines with the OEM polymer catch will cause premature wear and eventual feeding failures.

Community opinion on reliability is mixed. Many users report thousands of flawless rounds, while others experience occasional feeding issues, particularly with defensive hollow point ammunition. The Gen 3 S15 improved reliability over earlier generations, but the consensus among defensive-focused shooters is to run OEM 10-round magazines for carry and reserve S15s for range and competition use until personal reliability is established through extensive testing.