Hi scoccia,
I did some research in my books and internet and this is what i can come up with:
First photo On the foreground, with soldier standing next to it: A 122 mm M1938 Howitzer
In the middle: A 76,2 mm F-22 USV Divisional Gun
Second photo Havent figured this one out yet, still looking.
Third photo Two 45 mm M37/38 Antitank Guns + some 14,5 mm PTRD and PTRS Antitank Rifles on the ground.
Fourth photo On the foreground: A mix of 14,5 mm PTRS (5 shot magazine) and PTRD (1 shot) Antitank Rifles
On the left: Two 57 mm ZIS-11 Antitank Guns (production stopped in 1942) => not entirely sure about this, might also be another two 45 mm M37/38 Antitank Guns.
fifth photo Still looking
Hope this helps a bit. If you want i can give you some links to the sites i used to identify the guns.
Dolf