MAGPUL AMAG 21 SG9 9MM SIG P320 SST

Description

The Magpul AMAG for the SIG P320 is a purpose-built stainless steel magazine aimed at shooters who put serious round counts through their P320 and want a higher-capacity option that holds up to extended use. Stainless steel construction gives it meaningful corrosion resistance compared to polymer or carbon-steel alternatives, which matters for anyone who carries in variable conditions or stores magazines for extended periods without running them dry.

The 21-round capacity means you have a meaningful round count advantage over the standard flush-fit P320 magazines without resorting to a drum or adding a separate coupler. That additional capacity comes without sacrificing the flush feed-to-chamber geometry that makes the P320 platform reliable — the AMAG is engineered to match the SIG’s feed angle and follower geometry rather than adapted from a generic double-stack design.

The SST designation refers to the Silver Stainless finish, which is a functional choice as much as an aesthetic one: uncoated stainless steel has inherent surface hardness and corrosion resistance that a blued or parkerized finish relies on a coating to provide. For competition shooters running high-visibility gear or those who prefer to inspect their magazines for wear by sight, the finish also makes surface condition easier to read. This is a factory Magpul product built to the AMAG specification for the P320 — not a conversion of another platform’s magazine.