Glock magazines are durable, but their springs wear under the round counts competitive shooters put through them in a single season. USPSA Production and Carry Optics competitors running Glock 17, 19, and 34 platforms know that a feeding malfunction in a string is a stage-killer — and it's avoidable with routine spring replacement. Extended competition magazines (Glock 17 +5, aftermarket 140mm tubes for Production basepad use) put additional stress on factory springs due to increased stack height and follower travel. Replacement springs for factory-length and extended Glock magazines in 9mm and .40 S&W restore the tension that keeps rounds feeding cleanly under hard recoil impulses. This matters particularly on Glock 35 magazines used in Limited where the .40 S&W slide return is more aggressive. Whether you're maintaining eight factory 17-round mags or running extended tubes with aftermarket basepads, fresh springs are cheap insurance against avoidable failures. Compatible with Glock Gen 3, Gen 4, and Gen 5 magazines in 9mm, .40 S&W, and .357 Sig. Fast same-day shipping on most orders at Shooters Connection.