Barrel bombs are improvised devices that contain explosive filling and shrapnel packed into a container, often in a cylindrical shape such as a barrel. The devices continue to be dropped on towns all over Syria. Indeed, there have been several documented cases of their use in Iraq over the past months, and residents of the city of Mosul, which was recently taken by Islamic State in Iraq and the Levant militants, fear that Iraqi forces will use these devices as part of a government counteroffensive.
Barrel bombs are not a weapon of first choice; they are used when other options are lacking. Nations such as the United States that have more advanced militaries largely eschew unguided bombs in favor of more advanced, precision-guided munitions. When unguided munitions are utilized, they are generally specialized weapons used for specific tasks and fabricated in highly advanced factories on an industrial scale.
Even unguided munitions deliberately dropped over populated areas during World War II were far superior to the makeshift barrel bombs we see in the Middle East today. The British Tallboy dropped from Lancaster bombers over Germany is a good example. The Tallboy served a purpose similar to barrel bombs. The munitions were non-guided and thereby largely used indiscriminately against populated and industrial targets. The Tallboy, however, was well built, reliable and fitted with multiple types of fuses depending on the intended target. It was filled with Torpex D1 explosive, considered powerful at the time, and dropped using bombsights.
There are many disadvantages to barrel bombs. For starters, they have a high dud rate due to their often-shoddy construction in makeshift munitions factories. Though the Syrian regime has greatly improved these bombs over time, for instance by adding stabilizer fins and more reliable point-impact fuses, barrel bombs still often fail to explode as designed. The unexploded bombs are often recycled and utilized as improvised explosive devices by rebel fighters.
There is also no specific blueprint for barrel bomb construction, and they come in many different shapes and sizes. They also vary in the types of high explosive and shrapnel filling they use. While this enables do-it-yourself production at widely dispersed military bases and airports, it also complicates any effort to standardize more cost-effective mass production on an industrial scale.
Furthermore, barrel bombs are by nature highly indiscriminate. Their use often involves simply hand-pushing the munitions out of a helicopter over a populated target. This method leads to high levels of collateral damage, and civilians in many cities of Syria, for example, have paid a high price during barrel bombing campaigns.
For all these disadvantages, however, widespread barrel bomb use will continue in many asymmetrical conflicts where the state does not maintain an advanced air force. The current Syrian regime is a great example, with its lack of precision-guided munitions and a large number of defected pilots. Barrel bombs may not be the weapon of first choice, but they offer significant advantages. While shoddy and inefficient, barrel bomb construction is relatively cheap, easy and can be done in forward-deployed positions. Use of the weapon also does not require a highly skilled air force. As long as transport helicopters and pilots are available, these weapons can be utilized.
For an army that is not squeamish about civilian casualties — or that is in fact deliberately seeking them — barrel bombs also offer a unique and terrifying punitive weapon to terrorize the civilian population with. People can watch the slowly dropping bombs falling on their neighborhoods. Furthermore, as crude as these weapons are, they can be powerful, packed at times with relatively advanced high-explosive filling and large amounts of shrapnel.
It is thus no surprise that we have already seen these weapons used in a number of conflicts across Asia and Africa, including in Sudan, Syria and Iraq. In cases where a state is gradually able to acquire more advanced weaponry, superior munitions will eventually replace barrel bombs. Iraq, for instance, utilized barrel bombs at the same time the state was acquiring advanced and precise Hellfire missiles from the United States, but we are already seeing Baghdad's usage of barrel bombs decrease greatly as it receives well-armed helicopter gunships and Hellfire missiles in greater numbers.
Improvised explosive devices, whether buried at the roadside, launched at the tip of a crude rocket, or dropped from the air have been hallmarks of recent asymmetrical conflicts in the Middle East and elsewhere. These munitions, of which barrel bombs are a prominent example, will remain in wide use in future asymmetrical conflicts due to the unique advantages they offer to a resource-poor belligerent.