Simply put, a magazine is a container in which ammunition is stored, whilst a clip is a small piece of metal which holds rounds in place whilst outside the magazine, and sometimes within the magazine as well. Picture in your mind the bomb bay of a B-52
. Yes, you are there. The bay itself is the bomber's magazine, whilst the bomb racks on which the bombs are placed are clips. Now take your mind away from the bomb bay. Yes. Bring yourself back. Imagine that the B-52's bomb bay was in reality the magazine of a rifle, and that you were the size of an ant, indeed that you were an ant, and imagine that there are bullets hanging above you. Imagine that. In a way, there are bullets hanging over each one of us.
Since the advent of the repeating, magazine-fed rifle in the mid 1800s, there have been a variety of methods and mechanisms for storing multiple rounds about the soldier's person, inserting these rounds into the rifle's magazine and holding the rounds in place so that the rifle's mechanism may act upon them. A magazine is any container which stores ammunition. A building used to store ammunition is a magazine; a compartment in a ship which stores ammunition is a magazine, a bomber's bomb bay is a magazine. Rifle magazines are small containers which store rounds, usually equipped with a simple mechanism - a spring and a metal plate - which keeps the rounds stacked evenly, and which pushes the rounds into the rifle's action as it is cycled. Historically, the magazines of the earliest repeating rifles were integral parts of the rifle, often in the form of tubes running underneath the rifle's barrel, indeed contemporary shotguns still tend to use tubular, under-barrel magazines. These fixed magazines were fed with individual rounds by hand, a process familiar to millions from Westerns. At this point in time soldiers, cowboys and rustlers held the rounds about their person in bandoliers or ammunition boxes.
The tubular magazine had two big drawbacks, especially with the advent of the centre-fire cartridge and the pointed 'spitzer' bullet. The cartridges in a tubular magazine were arranged in such a way that it was possible for the tip of one bullet to ignite the primer of the next round in line, if the rifle was jarred sufficiently. A tubular magazine's capacity was limited by its length and spring strength, and furthermore such magazines were hard to clean and maintain in the field. Therefore, from the late 1800s, the integral rectangular box magazine became the standard. Some, but not all, rifle designs required that the rounds were furthermore held in place within the magazine with a small metal clip. The clip also kept ammunition held in a pouch or pocket aligned in the correct orientation.
A clip is, pedantically, a small piece of metal which holds rounds in place within a magazine. The M1 Garand mentioned elsewhere is an ideal example of this. The rifle's magazine stores eight rounds, which are held in place with a clip. After insertion the clip becomes an integral part of the rifle's mechanism, the action gripping and feeding from the clip, which is ejected once it has been expended. Rounds were issued to the soldiers in boxes, and were then transferred onto eight-round clips, which were fed into the M1's magazine. The terms 'clip' and 'magazine' have understandably become confused. Most military terminology is arbitrary and subject to change, and thus there is no reason to agonise over the supposed misuse of each term. The many definitions of the words 'gun' and 'cannon' are proof enough that the subject is trapped in sticky mud.
The removable magazine was an innovation pioneered during the First World War, initially for light machine-guns such as the BAR and Lewis Gun. Clips do nothing to keep ammunition clean and protected in the field, and furthermore they can break and allow the ammunition to fall out. The process of holding back the rifle's bolt, placing the clip into the receiver's guide rails, pushing the rounds down into the magazine and manipulating the bolt again was slow, fiddly, and liable to push dirt and mud into the magazine along with the bullets. By the end of the Second World War most of the world's battle rifles and all assault rifles were fed with removable magazines, their weight a small price to pay for their advantages. Removable magazines still have to be fed with bullets, however, either individually (often with the help of special tools), or from stripper clips.
There is a further complication, in the form of the stripper clip. To take an example, Britain's first repeating rifle was the Lee-Metford, eventually better known as the modifed Lee-Enfield. This was equipped with a removable box magazine which held ten rounds, although the magazine was in reality rarely removed. Instead, it was fed with stripper clips which held five rounds apiece. Unlike the clips described above, these stripper clips did not subsequently form part of the rifle's mechanism and were discarded after the magazine had been fed. Very few people nowadays bother to make the distinction between clips and stripper clips, rightly so.
Clips were also used to feed those designs of pistol revolvers which allowed unrestricted access to the back of the cylinder. Know as 'full-moon', 'half-moon' or 'speedloader' clips, these sped up the revolver's slow loading cycle. Very few automatic pistols were loaded directly with clips, the only significant design being the 'Broomhandle' Mauser C96. The earliest successful automatic pistol, the Borchardt, had been fed from a grip-mounted removeable magazine, a tradition maintained by its direct descendant, the Luger Parabellum, and the vast majority of subsequent designs. The large ammuntion capacity and relative novelty of the sub-machinegun has invariably resulted in such weapons also being fed from magazines.
Machineguns are generally fed from a 'clip' of their own, in the form of an ammunition belt. Belts are constructed of canvas or interlinked metal segments, the belt holding fifty, a hundred, two hundred rounds or more. To prevent these belts from flapping about they are often held in boxes which are attached to the machinegun, forming a large-capacity magazine. Various anti-aircraft, anti-tank and anti-ship guns are or have been fed with clips, for example the 40mm Bofors AA gun, although these are rarely confused with magazines on account of their size and prominence.