Unlike centerfire snap caps, these rimfire training rounds are explicitly designated as Action Proving Dummy Rounds. They are CNC-machined from solid aluminum billets and hard-anodized for precise SAAMI cartridge dimensions. While they are highly durable and perfect for teaching safe gun handling, function-testing actions, and diagnosing cycle or feeding issues, they are not intended for continuous dry firing. Because they lack a soft polymer/rubber primer section, repeated dry firing will eventually deform the aluminum rim.