Smith & Wesson M&P Magazine Extension by Henning

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. 

Factory 17 Round Magazine extension will increase up to 24 + 1 with the optional follower spring kit.