Smith & Wesson M&P Magwell Compatible Magazine Extension by Henning

Name: Smith & Wesson M&P Magwell Magazine Extension by Henning
Brand: Henning
SKU: H140-MS
Price: 44.95 USD
Availability: InStock
Rating: 5 (2 reviews)

Henning Group's Magazine Extension for Smith & Wesson M&P 9mm. This extension is made to make your magazine legal for USPSA 141.25mm gauge. For maximum capacity, add the follower kit.

Our latest design includes numbering dots, serrations for light side grab and a reinforced wall thickness.

We have two options for design and purpose:

Non-Magwell version for Carry Optics and general use
Magwell Ready specifically designed to work with M&P with magwell and no magwell.

Note: The non-magwell has the retention pin in the back which is the easiest to use. The magwell ready version has the retention pin in the front.

We recommend adding the optional MBX Extreme follower and spring kit to increase capacity to 24 + 1. The spring is longer and designed to work with our extension.

MBX "Ultra Max" Spring & Follower

*Note This Product will not lock slide back on last round fired

ATTENTION!
Before Inserting Magazine Into Firearm

New MBX competition follower & spring sets need to be loaded 4-6 times to capacity preventing follower popping out when new , insuring spring set and the follower sits down in tube when new, this avoids any slide contact and damange to spring and follower voiding warranty as the competition follower is NOT held down by the slide stop and has minimal surface area , the competition follower is designed once spring is set to sit 1/4-3/8 below top of feed lips thus avoiding damaging slide contact with follower once magazine is empty.

Our Magazine Parts Policies

2 Reviews

5
Pad and stock internals

Posted by David Simpson on Aug 28th 2025

Love these baseplates. Quick to clean if needed. 23 rnd with factory spring and follower (for me), Will be replacing all my baseplates with these.
5
Best extension IMO

Posted by Jordan on May 13th 2025

I've been running these for a while now, and they are by far my favorite. Super easy to put on and take off for cleaning during matches. With the CSRG spring and follower, I can get 25 rounds reloadable.