The ultimate upgrade for your Sig Sauer P365 380 pistol – the MTX 365 380 Plus, 3-Round SIG P365 10 rd to 13 rd Mag Extension! Transform your standard P365 frame into the extended grip length of the P365X/XL without compromising style or functionality by swapping the magazine. Made in the USA, this innovative and patented magazine extension is 100% reliable and designed to give you total control and improved grip on your firearm.
The SIG P365 Mag Extension is compatible with factory 10-round magazines for the standard P365 380 frame. Please note this only works with Sig P365 10 round magazines and standard frames. Our unique design enables the extender to work on the Sig mag body with inward-facing tabs where other extenders cannot be used. This also allows for seamless integration with the P365 platform without compromising the overall aesthetics of your firearm.
One of the main features of the SIG P365 Mag Extension is the custom-engineered spring, which guarantees unmatched reliability and ensures last-round bolt hold open. The MTX 365 +3 Round Magazine Extender also comes with a detailed installation video QR code to guide you through the simple process of adding this essential P365 upgrade to your firearm.
Furthermore, the SIG P365 Mag Extension provides the perfect pinky extension for tactile feel and control, allowing you to maintain accuracy and precision while shooting. In addition, the grip extension dramatically improves grip and control without having to go for the XL frame, giving you the confidence to manage your firearm in any situation successfully.
Lauded as one of the best P365 upgrades available on the market today, the MTX 365 +3 Round Magazine Extender with Spring for P365 takes your shooting experience to a whole new level. With its innovative, patented design, US 11,408,697 B2 and US 11,168,954 B1, and unparalleled reliability, this superior accessory is a must-have for any Sig Sauer P365 owner looking to enhance their firearm’s performance and take their shooting skills to new heights.
WILL NOT SHIP TO CA, CT, DC, HI, MA, MD, NJ, NY, OR, RI, WA









Jeff Gable (verified owner) –
Quick service and worked great. Well bulit and went together easy. The ones I received held 4 extra rounds instead of the 3 I expected so it was great. Will use XTech again and will recommend to my friends.
Michael Larson (verified owner) –
First one was a little hard to get on, second one easier after getting the technique down. The base fits well and moves well inside of the mag. Fits the 3 but can be over loaded to 4 extra but will rattle around in the well. Gor the range and ran 100 through the two mags without trouble. Even more comfortable grip than the 12 or 10 mag you can get with the p365, also these two upgrades are as expensive as a single 12 mag.
Ed Geiger (verified owner) –
Excellent product. As others have found you can fit 14 rounds in mags with this extension. I’ve run 200 rounds through my 2 extensions with no problems. The grip extension is perfect and is only about 1/8 inch longer in the front than a pinkie grip extension like the Sig or Pearce.