The gun In profile, you can see the 75cm barrel . (ok it's LEGO, you can see the 3cm barrel!)
Here's the sight
This is where the shells are loaded
Two russians sitting in the gun
close up of a russian
This anti-aircraft gun was mainly used during WWI but they were used during WWII by the Russians.
About the Gun:
Calibre: 75 mm x 660 R
Length of weapon: ?
Barrel length: 75 cm aka L/50
Length of rifling: 294 cm
Weight in action: 2556 kg
Weight traveling: Static
Fire-rate: 10 - 15/minute
Muzzle velocity: 750 - 806 m/sec
Magazine: None
Traverse: 360 degrees
Elevation: - 15 degrees, + 70 or + 75 degrees
Max. range: Horizontal range 12900 m
Country of origin: Russia
Ammunition types: AP HE (projectile 6,3 kg)