Magpul Amag 21 Sg9 9Mm Sig P320 Sst

The Magpul AMAG 21 SG9 9mm magazine for SIG P320 and M17/M18 platforms combines time-tested Magpul reliability with features that serious shooters and duty users depend on. Built with a corrosion-resistant stainless-steel body and polymer internals, this 21-round SIG 9mm handgun magazine handles high-round-count training sessions, competitive shooting, and duty carry without compromise. Whether you're running a full-size P320, compact variant, or sub-compact frame, the AMAG 21 SG9 feeds reliably every single time.

Magpul engineered this magazine with the controls that make a difference in real-world use. The high-visibility, controlled-tilt follower keeps rounds organized and feeding reliably under stress. A stainless-steel spring resists corrosion and maintains tension through thousands of cycles. The flared, easily removable floorplate lets you strip and clean the magazine in seconds—critical for shooters who maintain their gear seriously. Capacity-indicator windows run the spine of the magazine starting at five rounds and continue in single-round increments, so you know exactly how many rounds you're carrying without guessing.

Paint-pen dot matrix on the body lets you mark and organize your magazines by load, date, or duty status. No surprises, no guesswork, just straightforward function. Magpul designs, engineers, and manufactures every AMAG magazine in-house—you get the same quality control and consistency that makes their other products trusted by shooters across competition, hunting, and professional roles.

Key Features

• Stainless-steel magazine body resists corrosion in field or duty conditions
• High-visibility, controlled-tilt follower ensures reliable feeding and easy round count
• Stainless-steel spring for long-term durability and consistent spring tension
• Flared floorplate removes easily for fast cleaning and maintenance
• Capacity-indicator windows (5-round start, 1-round increments) let you verify load at a glance
• Paint-pen dot matrix for custom marking and identification
• Compatible with all P320 / M17 / M18 frame sizes (full, compact, sub-compact)

Specifications

Frequently Asked Questions

Will the AMAG 21 SG9 work with all P320 models?

Yes. This magazine is compatible with full-size, compact, and sub-compact variants of the P320, M17, and M18 platforms.

How do the capacity indicators work?

Windows along the spine show remaining capacity. They begin at the 5-round mark and continue in 1-round increments up the magazine body, so you can verify your round count at a glance without removing the magazine from the pouch or firearm.

Can I easily clean and maintain this magazine?

Yes. The flared floorplate removes without tools, allowing you to disassemble the magazine for routine cleaning and maintenance in seconds.

What makes Magpul magazines different from OEM SIG magazines?

Magpul designs, engineers, and manufactures the AMAG 21 SG9 entirely in-house. The stainless-steel construction, controlled-tilt follower, paint-pen dot matrix, and easily removable floorplate are all features Magpul added to improve durability, usability, and field maintenance compared to standard designs.