I came across this interesting snap cap during casework and thought I’d share since this is the first time our lab has encountered it. From an initial view, it looks like a 9mm Luger caliber Speer cartridge but upon evaluation, there is a blue acrylic material that is filled within the primer pocket area. There is no primer and no gunpowder component.
According to the manufacturer website:
"Our Ebay store offers a large variety of snap caps (training rounds). Each one is hand-made in our small family run business and we take pride in offering an affordable, superior quality product. They are made using actual brass and bullet to represent the real weight and feel, for an unmatched true training experience. Even though they contain no powder or primer, and no part of these can be used for live rounds, the primer pocket has been filled in with a soft set acrylic which helps to distinguish them from live rounds and assists with ideal weight." Here is a link to their store page for reference:
https://www.facebook.com/AllAmericanSnapCaps/