FWIW, the Astra 600 was never designed for or made in 9mm Largo. It was designed for the German order and never made in any caliber other than 9mm Parabellum (9mm '08).
All those Astra blowbacks have wicked recoil, the 400 is worst of all, feeling somewhat like hitting a baseball with a cracked bat.
The guns are actually something of retarded blowbacks because the hammer strut is deliberately placed at a mechanical disadvantage to slow the slide movement. That was not done with the Model 800 Condor with its external hammer, and the gun had some problems. Both the 400 and 600 are very rugged and very reliable guns.
The Germans purchased both the 300 and the 400 from Astra, but the 600 was designed specifically for the Germans in the 9mm Parabellum (9mm '08) caliber. 50,000 Model 600's were ordered and paid for in 1943, but only 10,450 were delivered before Spain was cut off from Nazi Germany by the Allied invasion of Southern France. Another 31,350 were made but were held in Spain until after the war when they were sold (again!) to West Germany and issued to police and customs guards.
Jim
