Realistic Magazine Management

Overview

Realistic Magazine Management is a concept found in some games, whereby each clip or magazine of ammunition is a uniquely identified object. Therefore, if a player ejects one magazine while it has some remaining bullets, those remaining bullets are either discarded and wasted, or the half-used magazine is saved for later, when it can be re-inserted, with the same amount of bullets.
 

Detailed Explanation  

Suppose the player is using a Sub Machine Gun that receives a magazine holding 30 rounds. The player has three magazines, for a total of 90 rounds. The player begins by shooting 20 of the 30 rounds in the first magazine. The player then decides to reload. The first magazine is ejected, and the second magazine inserted. The player now has 30 rounds in their weapon, in addition to a full magazine of 30 rounds, plus the remaining 10 rounds from the first magazine.  

The player now fires through all the rounds in their current magazine, and must reload. The player inserts the third magazine, and again has 30 rounds in their weapon, with only 10 rounds in reserve. This time, the player fires off 10 rounds from the current magazine, and decides to reload. In a typical shooter, the player would be left with 30 rounds in their weapon (ten in reserve, plus the 20 currently in the gun) but in a game with Realistic Magazine Management, the player would simply re-insert magazine #1, which had only 10 round remaining. After firing off those 10 rounds, the player would be able to re-insert magazine #3, with 20 rounds remaining. 
 

Chart 

Start: 
Magazine 1: 30 Rounds (in gun) 
Magazine 2: 30 Rounds 
Magazine 3: 30 Rounds 
Total: 90  
 
Fire 20 Rounds, Reload 
Magazine 1: 10 Rounds 
Magazine 2: 30 Rounds (In Gun) 
Magazine 3: 30 Rounds 
Total: 70 
 
Fire 30 Rounds, Reload 
Magazine 1: 10 Rounds 
Magazine 2: Empty
Magazine 3: 30 Rounds (In Gun) 
Total: 40 
 
Fire 10 Rounds, Reload 
Magazine 1: 10 Rounds (In Gun) 
Magazine 2: Empty
Magazine 3: 20 Rounds 
Total: 30 
 
Fire 10 Rounds, Reload 
Magazine 1: Empty 
Magazine 2: Empty 
Magazine 3: 20 Rounds (In Gun) 
  

Variations

Individual Magazine Tracking Style 

Some games simply track the individual magazines. This is accurate to the design described above, where a magazine with some remaining ammo will be later re-inserted with the same amount of ammo remaining. Therefore, if a player reloads his weapon before discharging it completely, he is, in effect, saving the ejected magazine for later. An example of this is SOCOM II.
 

Remaining Bullet Waste Style 

Other games do not track individual magazines, and ejecting a magazine with remaining bullets causes those bullets to be discarded. Therefore, the player is simply tossing spent magazine aside each time she reloads, with no regard to remaining bullets. An example of this is Medal of Honor: Frontline, with the M1 Garand.
 

No Mid-Magazine Reload Style 

Some games simply do not permit reloading until the entire magazine has been spent. An example of this would be the M1 Garand has featured in Medal of Honor.
 

Pros

The most common reason this style is implemented is to add realism and authenticity. Almost all real guns do indeed function in the manner described as Realistic Magazine Management. One is not able to simply reload mid magazine and find all the remaining bullets automatically transferred to another half-full magazine. A look at the attached games reveals that many of these are in fact games that strive for high realism.
A second reason, much less common, is games that want to increase the focus on item and inventory management. Some games focus on having the player manage their ammo and weapons carefully, and Realistic Magazine Management can add another layer to this. Along with this reason is that some games do this to balance weapons. A great example is the Medal of Honor series, in which the American M1 Garand is usually the most powerful rifle. To counter this, it often has a difficult clip management system, where the rest of the guns do not.
 

Cons 

The most obvious reason to avoid this style is because it can impinge on playability. Guns in games are generally not used the way they are in real life. For example, you almost never are tasked with mowing down hordes of zombies with your AK-47 assault rifle. When faced with such a task, it is important to always have a full magazine at the ready. Games with Realistic Magazine Management make this increasingly difficult, and it often takes away from the shooting aspect.
 
A second reason is the inherent difficulty. It is more difficult for the player to track, especially if the player has several guns, each with several magazines worth of ammo. Also, this is one more variable that the game has to accurately track.
 

Famous Examples  

M1 Garand from Medal of Honor

The Medal of Honor series has been mentioned several times for the M1 Garand. The M1 Garand is an American made rifle that was popular during WWII. The rifle was a fairly excellent weapon for its time and the first semi-automatic rifle issued to the infantry of any nation.  It used an "en bloc" clip of 8 rounds. The gun's design allowed for the clip to be automatically ejected when the last round was fired, and the loading chamber was held open, making for easy and quick reloads. In the first Medal of Honor game, the M1 could not be manually reloaded.  If the player was left with one remaining round, he must simply waste the final round in order to secure a fresh clip. This is, apparently, not accurate. It appears that M1's COULD be reloaded mid clip, however like most real weapons, the remaining bullets were wasted. This was how the gun functioned in Medal of Honor: Frontline. 
 

SOCOM: Navy Seals 

SOCOM was another example of a game that strove for a high level of realism. Players could only sustain one or two bullets before being incapacitated, darkness and sound were realistically modeled for stealth, and there was realistic magazine management. Interestingly, players discovered that the game tracked magazine as "used" when they were reloaded, so to keep the other team from obtaining good weapons during multi-player, players would reload their weapons at the start of each map. This caused the game to assume there was no remaining ammo when the player died, and "locked" the weapon from being procured by the other team.