Er spricht schlechtes Deutsch...
Does that mag well look long enough for .300 BO to you?Finally something new--433/437 (.300 Blackout version of the 433) will be the subject of a mag article on All4Shooters. Preview pic showing size of the 437 SBR next to a MP5 SD:
View attachment 282642
Also note altered controls and what appears to be a new pattern of bolt catch/release.