Forgotten Weapons has a nice slow motion video of StG-45(M) which ended up being the basis of H&K rooler-delayed blowback series.
https://www.youtube.com/watch?v=Sl2aOhQus0o
You can see more in-depth coverage of this gun from Ian from his older video
https://www.youtube.com/watch?v=WEPwmYcCPFs
From:Forgotten Weapons
