Henning Group Smith & Wesson M&P Magazine Extension
The Henning Group Smith & Wesson M&P magazine extension is a competition-focused basepad
for 17-round M&P 9mm magazines. Stonebridge Gunworks offers this extension in the available
Henning colors with your choice of a factory-follower spring setup for 23+1 capacity or the
MBX Extreme follower and spring kit for 24+1 capacity.
Smith & Wesson M&P 9mm
17-Round Magazine Base
23+1 or 24+1 Options
USPSA 141.25mm Gauge
Practical Shooting Ready
Built for Practical Shooting M&P Setups
This Henning Group magazine extension is a strong upgrade for Smith & Wesson M&P shooters
building a Practical Shooting, Carry Optics, Limited Optics, Limited, or Open division setup.
The extension is machined from 6061-T6 billet aluminum and shaped as a true extension of the
internal magazine tube profile for reliable feeding with the correct spring and follower setup.
For Stonebridge Gunworks customers, we are offering this product in two useful configurations:
a higher-capacity MBX Extreme follower and spring setup for maximum round count, or a Henning
spring setup that uses the factory follower for shooters who prefer that arrangement.
Option 1: Henning Spring Kit for Factory Follower
- Uses the factory M&P magazine follower
- Designed for 17-round M&P 9mm magazines
- Capacity target: 17 to 23+1
- Good choice for shooters who want added capacity while retaining the factory follower style
- Recommended for competitors who prioritize a conventional follower setup
Option 2: MBX Extreme Follower & Spring Kit
- Uses the MBX Extreme follower and spring kit
- Designed for 17-round M&P 9mm magazines
- Capacity target: 17 to 24+1
- Maximum-capacity competition setup
- Does not lock the slide back on empty
Available Colors
Choose the basepad color that best matches your M&P competition build.
Black
Silver
Red
Blue
Orange
Purple
Green
Configuration Comparison
| Configuration |
Follower |
Capacity Target |
Slide Lock on Empty |
Best For |
| Henning Spring Kit for Factory Follower |
Factory M&P follower |
17 to 23+1 |
Factory follower style setup |
Shooters who want added capacity while keeping the factory follower arrangement |
| MBX Extreme Follower & Spring Kit |
MBX Extreme follower |
17 to 24+1 |
No slide lock on empty |
Maximum-capacity competition magazines where round count is the priority |
Product Features
- Henning Group magazine extension for Smith & Wesson M&P 9mm magazines
- Designed for 17-round factory magazine bodies
- CNC machined from 6061-T6 billet aluminum
- Designed to fit the USPSA 141.25mm gauge
- Useful for Carry Optics, Limited Optics, Limited, and Open division builds
- Updated Henning design with numbering dots, side serrations, and reinforced wall thickness
- Available in Black, Silver, Red, Blue, Orange, Purple, and Green
Compatibility
| Compatible With |
Important Notes |
| Smith & Wesson M&P 9mm 17-round magazines |
This product is intended around the standard 17-round M&P 9mm magazine body. |
| M&P 2.0, M&P Metal, M&P Metal Competitor, and similar full-size M&P 9mm competition builds |
Confirm magazine body compatibility before ordering if using non-standard magazine bodies. |
| Competition magwell setups |
Henning notes compatibility with several tested magwells, including Ed Brown and the S&W factory magwell. Some grip retaining pins may require modification for the magazine to drop free. |
Important Capacity and Function Notes
Capacity can vary slightly based on magazine body condition, spring break-in, ammunition length,
follower selection, and installation. The MBX Extreme follower and spring kit is a competition
capacity setup and does not lock the slide back on empty.
Magazine capacity laws vary by state and locality. This product may not be available for shipment
to restricted locations. It is the customer’s responsibility to understand applicable local laws
before ordering.
Recommended Pairing
This magazine extension pairs well with a Smith & Wesson M&P Metal Frame Practical Shooting build,
especially when combined with a competition-focused trigger setup and reliable match magazines.
Stonebridge Build Support
Building an M&P Metal or M&P 2.0 competition pistol? Use the links below to continue building
out a Practical Shooting-focused setup.
