The Economics of the Bullet
Steel, Copper, Lead, and Gunpowder
The Bullet; Generally a piece of lead encased in copper, fired with gunpowder. They come in many sizes and varieties. Whether it is 9mm, 45ACP, 223Rem, 5.56, or 7.62, they all have something in common, they are all pretty cheap. Depending on where you go, you can buy the most expensive of those, 7.62x36, for 220 dollars for 1000 rounds. which is 22 cents per round. for many, that is pocket change. however, 1000 rounds really isn't much. thats 33 30 round magazines or a nice 50 20 round magazines. that may be enough for a squad of 5 for one outing, that is pushing it. on the battlefield, tens of thousands of rounds can be fired. all of them have a price tag, and all of them must be produced. companies like Remington outdoor and sturm and ruger make hundreds of millions off of small pieces of punched metal with explosive powder in them.
So how do companies distribute so many bullets so quickly and cheaply?
Production
Bullet production is not as simple as it may seem. most smaller rounds, such as 22 caliber, are formed by using punching dies in thick lead rods to form the shape. but others are made by pouring molten lead mixed with antimony into a cast. some bullets are then coated in copper. the cases of the rounds are all made in the same way. a brass sheet is punched into small circles, then pressed out in expansion dies until it is the right height, then the cases are cinched at the top to taper them. the primer, which is a small explosive on the bottom of the round, is inserted in the bottom of the case. then the case is filled with powder, then the bullet is inserted and crimped into the case. some final rounds are checked for quality, usually by running a few thousand through a firing test, then they are either placed in ten to twenty round stripper clips for easy loading, or they are simple tossed into wooden or plastic crates and sent to the shipping phase.
Shipping
as it turns out, most people and companies can, with proper safety, simply ship ammunition with pretty much any mail service. UPS simply requires a small tag and that the ammo is shipped separate of any firearm. however companies will usually ship on specified service contracts. they may buy out whole fleets of aircraft to move mass quantities of ammunition. the ammunition is kept on planes as much as possible for safety, as if a car was to crash on a city street carrying 5 tons of bullets, well the aftermath would not be pretty. aircraft are generally safer and if they do crash and explode, its far less likely to hit anyone as bullets do not usually travel in any kind of accurate line when not fired from a gun. bullets are also shipped in freight boats and trains, usually in large crates filled with the individual ammo crates. this option is usually for really high volume shipping, as boats and trains can carry tons of ammunition without much issue.
Selling
the final step is shelving and selling. this is by far the easiest step as the manufacturer has little to do with this part. when demand is higher, the seller has to deal with that, not the producer. selling bullets is as easy as selling alcohol. as long as the buyer is of the age required, which is usually 18, they are good to go. the only exceptions are handgun rounds which require the buyer to be 21 and rounds withheld due to licence requirements. but the same is true for full guns anyway.
TLDR
Essentially, the process can be simplified to this; Bullets are made of cheap materials, shipped in the cheapest way possible, and sold in such high quantities that all losses are quickly rectified.
This is one of the shipment containers for ammunition. they are steel boxes that ship with belts or just assorted rounds in them. there are also wooden crates (not shown) that are basically the same. (fun fact, the red tipped rounds are tracers, they are there so, every fifth round, you can tell where your rounds are going, if you could not see them due to low light or something)
This is a bullet production factory. you can see many boxes of rounds that have yet to be packaged for shipping.
Closing
Bullets are an important part of the american economy, whether you like it or not. they are made for civilian and military purposes and the military can spend millions of dollars just to buy the ammunition for one helicopter or plane. in the case of bullets, its all about supply and demand, the more people want, the more will be made, and the good thing is there will likely never be a time when demand exceeds supply, because there are just so darn many. you would be hard pressed to find any place in america with a shortage of bullets. and while some argue that that is a bad thing in itself, you've gotta admit, it is rather impressive that there are so many in the first place.