Henning's extended base pads are legal for USPSA Limited and Open competitions. Attached to the factory magazines they extend the magazine to 141.25mm length (5.56"). Whether you want to be competitive or not, these pads will extend the capacity of your Sig Sauer P320 magazines.
You can use the extensions with the factory follower and spring and achieve plus 22 plus 1 reloadable capacity.
For competitive shooters (USPSA), we recommend also getting the Rune Tactical follower and springs that makes 23 plus 1 reloadable!
Works for both 9mm and 40 S&W magazines!
These extensions are designed to work with the Sig Sauer P320 X-Series models (XFIVE Legion, AXG Scorpion, RXP XCOMPACT, XFULL, XCOMPACT, XVTAC, RXP XFull-Size). It will also work with the Wilson Grip Module and other after market grip models with a flat bottom. If you want to use it with standard P320 grip modules where the back strap comes down, it will require modification of the grip module to allow for relief for our steel detent. This is how the extension is held in place so standard P320 grip modules will need a relief cut into the grip.