Frontal armor was 76mm. Thats thinner than the Panzer's, and the panzer seems none too resiliant to shells.
T-34, for comparison, has something around ~100mm with armor slope factored. With APDS it might be better than the T-34, but with APCR it would be just slighly inferior IMO.
If they gave us APDS, then (on paper) its gun would be slightly superior to even the KwK 40 and M1 76mm, but who knows how much "damage" HTC would have it do.