This magazine extension is made specifically for the Sig Sauer P320 21-round magazines to fit the USPSA 141.25mm magazine gauge. When combined with a Grams Follower Kit, it will extend the capacity to 23 + 1 rounds.
You can also use it with the factory follower and spring which will increase the capacity by 1 round. It 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.
TWO OPTIONS ARE AVAILABLE ON EXTENSION SIZE / FIT:
1. GO-GAUGE: This means the basepad can be installed on any brand new 21-round magazine and fit the USPSA gauge. You're good to go for the match!
2. NO-GO-GAUGE: This extension is .025" bigger which means the rear top edge of the magazine tube's feed-lips needs to 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 give you a little easier magazine seating when you load it up with 23 rounds.