This picture shows a captured Wehrmacht data sheet for the PaK 97/38:
The gunners who used this sheet had two types of ammunition: a 6.8 kg Polish AP shot (the 7.5 cm K.Gr. Pz. (p)) and a 4.8 kg ‘French’ HEAT round (the 7.5 cm Gr.38/97 HL/C (f)). I’d guess that the Germans may also have used the other HEAT and HE rounds listed in wikipedia.