Armor steel (STS) was developed in 1910, so I looked into this thing a little more and found the link above.
The armor had some decent stopping power and was rated for Mauser AP rounds in the front and regular service rifles (ball rounds) in the sides. Both ratings were for projectiles being shot at 90°, so that is fairly significant. (Any other angle, the energy of the projectile causes it to deflect.)
https://tanks-encyclopedia.com/ww2/italy/ansaldo-miasmoras-1935/
Armor steel (STS) was developed in 1910, so I looked into this thing a little more and found the link above.
The armor had some decent stopping power and was rated for Mauser AP rounds in the front and regular service rifles (ball rounds) in the sides. Both ratings were for projectiles being shot at 90°, so that is fairly significant. (Any other angle, the energy of the projectile causes it to deflect.)
But yeah, the whole design is just impractical.