Family photo!

So, who can tell me what all of these weapons are? And what they have in common?

Continue on for details…

Yep, if guessed roller locking, you are correct. The machine gun at the bottom is of course an MG42, the first successful roller locked firearm. The rifles are in chronological order, from left to right:

Gerat 03 – Roller locked variant of the G43
Gerat 04 – A 7.92×33 Kurz version of the Gerat 03
Gerat 06 – Gas operated, roller locked, stamped receiver assault rifle
Gerat 06H – Retarded roller locked, stamped receiver assault rifle, produced as the StG45
CETME – Scaled up retarded, roller locked rifle, developed in Spain – the first mass-production gun in the family
HK91 – The refined version of the CETME
HK93 – The 91 was pretty popular, so why not sell it in 5.56mm too?
MP5 – The standard against which all modern submachineguns are judged
And hiding down in the back, the CZ52 pistol. Because the Czechs just couldn’t use what the Russians told them to.

There aren’t that many different ways to design repeating firearms, and it’s neat to be able to see a pretty complete lineage of a particular design all at once.