In airsoft, you have two basic types of magazines: High Capacity and Mid Capacity. The main difference between these two types is the method in which they are loaded and feed your airsoft guns.
HIGH CAP MAGAZINES
A high capacity is essentially a hollow magazine body that can hold a lot of ammo. There is an internal gearing mechanism with a wheel that you have to turn manually. This interacts with the gears inside and loads BBs up a chute and into your gun from the main compartment. The magazine can be wound a certain number of times before you cannot wind it further and allows the gear to slip to prevent damage inside to the components or spring. Once all the spring tension is used up, you will have to wind the magazine again. A typical high cap magazine can go through three or more winding cycles to completely deplete all the ammo in the mag. This style of magazine does not require any tools to operate.
MID CAP MAGAZINES
The mid-capacity magazine is more traditional with a simple spring and a plunger/follower. You would load BBs into the top of the magazine using a loading tool. The loading tool is a device that manually transfers ammunition from the tool into the magazine with the press of a plunger. You will transfer ammo from the tool into the magazine until you feel you can no longer depress the plunger. That means the spring is fully compressed, and the magazine is full. It requires no further loading or winding after it is loaded and is ready to go the moment you insert it into the gun. It will feed BBs to the rifle until it is completely out. These generally feed very reliably and take longer to wear out. The BBs also don’t move around inside the magazine body, making loud noises.
Okay, now that you know what kind of mags exist for AEGs, it’s time to discuss logistics. If you’ve just picked up your gun brand new, chances are you will have just the high cap it comes with. Very few guns might come with a mid-capacity magazine as standard instead. A few brands may include a second magazine for added value which is nice.
To get an idea of how many magazines you should have, you should ask yourself how often you think you’ll be shooting in a day. This will depend on the size of the field you’re playing in, what kind of role you might play, and if there are large teams and respawn rules. If you’re at a particularly large and busy field, you’ll probably have more things to shoot at and therefore run through more ammo. On the other hand, if you have rented and played at a field before, you might already have an idea of how you play and how much ammo you would expend in a round.
With a high cap, you could carry some bottled BBs, reload out in the field, and get by with one magazine. Though if you are in a pinch, this might be slow. Though it is not ideal, you could do it for now. If you fancy yourself a happy trigger shooter, you may need more magazines for sure. And also, consider the number of players you might see on the field. If your local field has only small groups, you won’t need that many mags and ammo. If your field is particularly busy or you are going to an event, again, carry more magazines. Generally, if I see you starting out with an M4, I’d carry at least two high cap magazines (= 600 rounds in total). Even more than that is ideal for the larger venues. Some guns like the AK hold a lot of ammo, and it would be more than sufficient with just one.
You can see all of our airsoft gun magazines here at Just BB Guns; however, please contact us if you have any questions about airsoft mags.