This magazine extension is explicitly made for the Sig Sauer P320 21-round magazines to fit the USPSA 141.25mm magazine gauge.
You have three options for follower and spring:
- Factory follower and spring will increase capacity from 21 to 22
- Rune Tactical will increase capacity from 21 to 23/24 (depends on Go and No-Go gauge)
- MBX Extreme will increase capacity from 21 to 23/24 (depends on Go and No-Go gauge)
You have two options for magazine extension length and fit:
- Go-Gauge. You can install it on any brand-new 21-round magazine to fit the USPSA gauge. You're good to go for the match!
- No-Go-Gauge. This extension is .025" bigger, meaning the rear top edge of the magazine tube's feed lips must be filed/ground down to fit into the USPSA gauge. If you already have other aftermarket extensions you've probably already done this. And the .025" extra room will make it a little easier for magazine seating when you load it up to either 23 or 24 rounds.
- The extension can also be used with 15 or 17 round magazines, and will fit inside the carry magazine well found on the Sig Sauer AXG PRO.
Our extension is machined from 6061-T6 aluminum and anodized. We offer them in black, red, blue and silver. When used with the factory follower and spring, the factory locking plate must be removed and not used. We use a spring-loaded detent to secure it to the magazine. It makes it super easy to take it on / off for magazine cleaning, and it is 100% secured. The detent is made from stainless steel and finished in Black Nitride for long life.