Thanks friends.
The following is from january 1944 and seems to be a compilation of Me-110 and Me-410 guncameras, all shooting against B-17 and B-24, is a rare newsreel because it also includes an interview with "Zerstörer" pilots.
The tube hold by a ground mechanic at 2:31 is the 20mm Mauser MG 151 quick change barrel