ProMag Ruger SR40 .40 S&W 10-Rd Blued Steel Magazine

The ProMag RUG21 is a replacement magazine engineered for the Ruger SR40 .40 S&W pistol. Designed as a direct-fit spare, this magazine feeds a wide variety of factory .40 S&W loads without modification, giving SR40 owners a reliable backup for range use or training.

The magazine body is constructed from heat-treated blued steel finished with a black oxide coating for corrosion resistance and long service life. Internal components include an injection-molded Technapolymer follower, lock plate, and base plate, all engineered for consistent feeding. An anti-fatigue spring maintains steady tension to support follow-up shots.

Holding 10 rounds of .40 S&W, the RUG21 is a solid spare-magazine option for any SR40 shooter. ProMag has engineered this magazine as a direct-fit replacement for the factory SR40 magazine.