Jungle style

The term "jungle style" refers to the practice of taping or securing two gun magazines together, with one taped upside down while the other is inserted into the rifle.

A jungle style configuration is used to speed up the process of reloading, since the other magazine is attached to the exhausted magazine, as opposed to being in a pouch, or other ammo storage unit. The downside to the configuration is that it can increase the weapon's chance of jamming, as one magazine and its ammunition is normally left exposed to dirt and the elements. Some firearms manufactures have designed their magazines with studs or cradles that allowed them to mate together without the need of tape or clamps, such as the Heckler & Koch G36 and SIG SG 550; typically, these devices mount the magazines side-by-side and upright, so as to reduce the risk of ammunition falling out or becoming dirty.

History
The practice of jungle style magazines originated in World War II with the introduction of 30-round magazines for the M1 Carbine, M3 "Grease Gun" and Thompson submachine gun. Taping these magazines together in order to speed up reloading became so common among troops that the U.S. military introduced the "Holder, Magazine T3-A1", which came to be referred to by some infantrymen as the "Jungle Clip". This metal clamp holds two M1 Carbine 30-round magazines together without the need of tape.