Vertical or horizontal magazine placement on your duty belt?
Do you prefer chocolate or strawberry ice cream, deep nights, or day shift? The choice is ultimately yours, just like choosing between horizontal or vertical magazine orientation on your duty belt. Either way, it is essential to how you perform as a police officer.
First of all, be clear; there is no "one perfect way." And, as always, I am a big fan of doing what works for you. However, to make the best decisions, you must learn the "whats" and particularly the "why" behind the "whats."
In this case, I am going to suggest vertical magazine orientation on the off-hand side of your duty belt with cartridges always facing your strong hand.
The concept is simple. When it's time to dump a magazine from your duty weapon, the magazine well is typically perpendicular to the ground with a very slight cant running 1 to 7 o'clock or 11 to 5. If your magazines are placed vertically, on the off-hand side, then everything stays linear. The magazine well and magazines are vertical.
Functionally, I recommend drawing your elbows in close to your chest and looking "through" your weapon as you reload. This technique allows you to maintain a visual on the threat and develop a reference point for where the weapon is during reloads.
When you reach for the magazine, you should "go deep," gaining a robust and intentional grip on the magazine. Extend your index finger down the front face of the magazine as you slide it firmly into the magazine well. Seat the magazine firmly, but don't slam it into place.
Of course, the most important thing of all is gross motor skill development. In other words, practice safely, but practice often.
Watch this video on magazine placement.