I have always wondered why gun magazines are curved. Especially knowing nothing about guns. The overly simplified answer comes down to the shape of the ammo and how each bullet stacks on top of each other within the magazine to feed the firearm correctly.
I believe nobody asks the question because nobody wants to look like an idiot. I have heard some gun enthusiasts blurt out, “isn’t it obvious?” Well, no. It’s not obvious for people who have never been around guns. If you are like me, you’ve might have asked yourself the same question. There are straight and curved magazines so the curiosity would be pretty natural for anyone who didn’t know.
Let’s cover the main aspects of why gun magazines are curved in more detail.
Why curve certain magazines?
With ammo that has more of a cone shape and is tapered off (usually rifle ammunition) there will be more space in between the tip of the round than at the base when next to another round. This gap is likely to grow when more rounds are in the magazine. You want the gap between rounds at the front of the magazine to be as small as possible so the receiver can load rounds straight and effectively into the chamber.
Conical Shaped Ammo
Cone shaped ammo is best for aerodynamic bullet travel.
Conical ammo naturally stacks up and starts to curve.
Why are bullets conical shaped?
Every type of ammunition cartridge is different. All cartridges have various shapes, measurements, grain weights, and bullet heads. They all look different and generally have a slight cone shape to the base hence the reason they stack differently when on top of each other. This becomes a problem once a high amount of ammo start to stack up.
How much curve is needed per bullet type?
It all depends on how the ammo stacks up. With each cone shaped round having different dimensions, the various angles give each stack of ammo more or less of a curve. This is why some gun magazines have more of a curve than others.
The examples below show how much curve there is between various firearms and magazines.
The AK magazine is one of the most curved magazines in the Assault Rifle category. The 7.62x39mm round has quite a taper and more cone shaped than most of the other rounds of similar caliber.
AR15 magazine example
As you can see, the AR15 magazine is much less curved at 30 rounds versus the AK. This due to the 5.56x45mm round having much less of a cone shape than the 7.62x39mm. So much less in fact that the early M16A1 rifles carried a 20 round magazine which were straight.
Why some guns still use straight magazines
There are a number of high capacity magazines that are straight. Usually they are pistol or sub machine gun magazines. Why? Because the rounds chambered for these weapons are smaller in length. This limits the cone shape that usually happens in larger and longer ammo types and reduces the taper at the top of the bullet tremendously. This gets rid of the need to use curved magazines for these guns.
9mm is is pretty much the standard pistol ammo around the world. As you might notice, its casing shape is very straight. This will limit the need to go with a curved magazine.
This is the standard AK round. The conical shape is much more noticeable on this rifle round than the 9mm round. The curve is necessary for the rifle to acquire an adequate bullet feed from the magazine.
As you can see in the above video, they go into great detail on how and why magazines are shaped the way they are.
I know after learning about why gun magazines are curved, it all makes sense. I hope all this information answered your questions as much as it answered mine.
Use what you have learned and get out to the range and practice. Remember – Practice Makes Proficient.