The fastest reload is when you don’t have to do one. That is why high-capacity magazines or drum magazines are awesome. However what if you don’t have those types of magazines? How can you make your regular reloads faster? It comes down to this—economy of motion. Why waste time reaching for a spare magazine from a pouch either on your waist or on your chest? Coupled magazines are the way to go.
Coupling mags is easy.
Some companies make couplers themselves.
CZ-USA has couplers for their Scorpion Evo 3 magazines.
Magpul makes a mag coupler to join two PMAGs together.
There are also 3rd party mag couplers.
I coupled two 35 rd magazines for my M&P 15-22 with a Mission First Tactical mag coupler. Which you can see below.
Running coupled mags is faster than traditional single mag reloads.
Yes, there are some rather fast people out there who can reload in a blink of an eye. But the simple physics of it all dictates that a person reloading from a coupled mag will be faster than when they do a traditional reload. You just don’t have to move your hand as far to retrieve the next magazine.
For bullpup rifles, coupled magazines can be an issue because you could have a spare magazine on the outside of the gun and it could interfere with your shooting arm. Here is a trick shown by an Israeli woman from Zahal about offsetting your coupled magazines and twisting them when reloading a Tavor.