I have seen them in stores here and I have some that my father bought probably 30+ years ago. They are quite powerful for only being primer powered, they are a lot more dangerous than the rubber bullets that use regular brass with the flash holes drilled larger. Having used both I would recommend getting the X-Ring Rubber Bullets, you can stop them with a towel hanging off the back of your target cardboard, the Speer plastic bullets will sail through that.
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