The legality of steel core ammunition, also known as armor-piercing ammunition, varies depending on the jurisdiction and specific laws in a given region or country. In this answer, we will discuss the general principles surrounding steel core ammunition, including its composition, potential dangers, and legal status in various jurisdictions.

Steel core ammunition is a type of ammunition that features a projectile (bullet) with a steel core, which is typically surrounded by a jacket made of copper or other materials. The steel core is designed to penetrate armor or hard targets, making it capable of piercing through bulletproof vests, vehicles, and other fortified objects. This characteristic of steel core ammunition has led to its classification as armor-piercing ammunition, and its regulation is typically aimed at preventing its use in criminal activities or against law enforcement or military personnel.
One of the main concerns associated with steel core ammunition is its potential to pose a higher risk of penetrating protective barriers compared to traditional lead-core ammunition. This can be a concern for law enforcement, as it may increase the risk of harm to officers or innocent bystanders, and for public safety in general. Due to these concerns, many jurisdictions have enacted regulations on the use, sale, and possession of steel core ammunition.
In the United States, for example, steel core ammunition is regulated under federal law. The Gun Control Act of 1968, as amended by the Law Enforcement Officers Protection Act (LEOPA) of 1986, prohibits the manufacture, importation, and sale of armor-piercing ammunition for handguns, with certain exceptions for law enforcement and military use. However, steel core ammunition for rifles is not regulated under federal law in the United States, and it can be legally manufactured, imported, and sold for civilian use.
Some states within the United States, however, have additional regulations on steel core ammunition. For example, California, Connecticut, and New York have restrictions on the possession or sale of armor-piercing ammunition, including steel core ammunition, regardless of the type of firearm it is intended for. Other states may have specific regulations or restrictions on the use or possession of steel core ammunition, and it is important to be familiar with the laws in your specific state or jurisdiction.
Outside of the United States, the legality of steel core ammunition varies widely depending on the country. Some countries, such as Canada and Australia, have restrictions on the possession or use of armor-piercing ammunition, including steel core ammunition, regardless of the type of firearm. Other countries may have specific regulations or restrictions on steel core ammunition based on the type of firearm it is intended for or its potential to pose a threat to law enforcement or military personnel.
It is worth noting that regulations on steel core ammunition may change over time, and it is important to stay updated on the current laws and regulations in your jurisdiction. Violating regulations on steel core ammunition can result in serious legal consequences, including fines, confiscation of firearms, and criminal charges.
It is also important to note that the term “steel core ammunition” can sometimes be confused with other types of ammunition that may have steel components, such as steel-cased ammunition, which refers to cartridges with steel casings instead of brass or other materials. Steel-cased ammunition is generally legal and widely available for civilian use, but it is different from steel core ammunition in terms of its composition and capabilities.
In conclusion, the legality of steel core ammunition, or armor-piercing ammunition, varies depending on the jurisdiction and specific laws in a given region or country. It is important to be familiar with the laws and regulations on steel core ammunition in your specific jurisdiction to ensure compliance with the law. Violating regulations on steel core ammunition can have serious legal consequences, and it is essential to stay updated on the current laws and regulations regarding this type of ammunition.