A magazine holder can be worn in many different positions on your belt or even in your pocket. Whether it is in a vertical position or even in your pocket, our preferred method is in the horizontal orientation. There are many reasons we prefer this orientation that we have discussed in a few different articles and posts.
Although I do not have data to back this up from the gun manufacturers themselves, we are seeing an up tick in the Magholder being purchased for the M&P Shield magazines. This pistol has been around since initially introduced in 2005.