S20 20-Round Magazine for Glock 43X/48

The Shield Arms S20 is a 20-round steel magazine for the Glock 43X and Glock 48. It takes the patented staggered feed geometry that made the S15 the standard slimline Glock magazine and builds it out to 20 rounds in one continuous steel body, rather than stacking an aluminum extension onto a 15-round tube.

The trade is length. Twenty rounds of 9mm in a slimline-width body extends below the grip frame, so the S20 is a spare magazine rather than the one that lives in the pistol for concealed carry. Shield Arms positions it for the mag pouch, the range bag, and the nightstand, with a flush-fit S15 in the gun.

The body carries integrated over-insertion tabs stamped into the steel, which stop the magazine from seating too deep in the magwell and pushing the feed lips out of alignment. Finish is the same QPQ nitrocarburizing treatment used across the S-Series. Like the S15, the S20 requires the Shield Arms steel magazine catch and will not run correctly on the factory polymer catch.