For the 9mm I run guns ( state side) they have some but for short 12 gau ( rare birds ) you my have to find someone that will make them for you . Not hard to do if your willing to try just get some cheep bird shot shells( low brass) and cut the shell in half with a razor knife just above the shot wad and hot glue to seal it .
For normal 9mm blanks marstar .
https://jdairsoft.net/trmr/trmr-e1/trmr-e1-x4-s5
Thats the toy. Uses different sized blanks. Think flash bang.