Description
The Magpul AMAG 21 SG9 is a 21-round 9mm magazine for the Sig Sauer P320 and M17. The body and spring are heat-treated stainless steel, and the follower and floorplate are polymer. It gives you four rounds over a factory 17-round P320 mag in a tube that still fits most double-mag pouches.
Magpul says it fits all full-size, compact, and sub-compact P320, M17, and M18 variants, with the mag sticking out below the grip on the smaller frames. The follower is high visibility with controlled tilt, and the stainless spring is built for long service. Witness holes start at five rounds and count every round after that. The flared floorplate pops off without tools for cleaning, and there is a paint pen dot matrix on the body so you can number your mags. Magpul lists it at 4.0 oz empty. Made in the USA. One magazine.
Division note: a 21-round mag is fine for USPSA Carry Optics and Limited Optics if it fits the 141.25 mm gauge with the factory floorplate, and for Open with an extended base pad. Check your division rules. It is over the 10-round limit for Production.
Specs
- Fits: Sig Sauer P320, M17, M18, all frame sizes
- Caliber: 9x19mm
- Capacity: 21 rounds
- Body / spring: Heat-treated stainless steel
- Follower / floorplate: Polymer, high-visibility controlled-tilt follower
- Weight: 4.0 oz empty
- Witness holes: From 5 rounds, single-round steps
- Made in: USA
- Part number: MAG1465-SST
Who it’s for
P320 shooters in USPSA Carry Optics, Limited Optics, or Open who want 21 rounds for stage planning, and anyone who wants a stainless spare that costs less than a factory Sig mag.
Who should skip it
If you shoot Production or IDPA, you are capped at 10 or 15 rounds and this mag buys you nothing. If you need a flush-fit mag for a compact P320 carry gun, this will hang out the bottom. We also carry the Magpul AMAG 17 for P320 if you want factory-length.
