This 12-gauge breaching cartridge is specifically designed to gain access through:

The correct answer is that the 12-gauge breaching cartridge is specifically designed to gain access through light doors and entryways. This type of ammunition is engineered to be effective against less fortified structures. Light doors and entryways often refer to those made from materials that do not require heavy-duty breaching methods.

These cartridges typically contain a range of projectiles that create a significant impact, allowing for quick access to rooms or buildings under controlled circumstances, which is a crucial aspect of tactical operations. They are safer for use in environments where excessive force could lead to collateral damage or unintended consequences.

Reinforced doors, security barriers, and metal gates require different approaches and heavier munitions because they are made of sturdier materials that can resist the impact from lighter breaching rounds. Therefore, the focus of this specific 12-gauge breaching cartridge is on achieving effective entry through structures that do not offer significant resistance, making it ideal for the intended purpose of breaching light doors and entryways.