Which component is primarily used for training purposes in the 30 mm ammunition context?

The primary component used for training purposes in the context of 30 mm ammunition is dummy rounds. Dummy rounds are designed specifically for training exercises; they mimic the weight and dimensions of live ammunition but lack explosive components and propellant. This allows personnel to practice loading, unloading, and handling procedures safely without the risks associated with live munitions. Using dummy rounds also helps to familiarize trainees with the ammunition's characteristics and operational protocols without the potential hazards that come with live fire scenarios.

Live rounds are intended for actual combat use and are not suitable for training due to safety concerns. Incendiaries are specialized munitions designed to ignite fires and are used in specific operational contexts rather than training. Subcaliber rounds, while useful in certain training applications, typically refer to ammunition used in conjunction with larger caliber weapons or training devices, which may not be directly related to the specific training on 30 mm ammunition handling. Thus, dummy rounds stand out as the safest and most effective option for training related to 30 mm ammunition.