Interestingly enough, the Panther DID perform better on armor penetration:
KwK 42/L70 (Panther
Durchschlagsleistung bei 90° (60°) Auftreffwinkel (mm):
7,5 cm PzGr 39/42 // 7,5 cm PzGr 40/42
0 m distance 167 (133) // 230 (197) -
450 m distance 149 (121) // 198 (154) -
900 m distance 133 (110) // 170 (123) -
1350 m distance 118 (99) // 145 (99) -
1850 m distance 104 (89) // 122 (80) -
2300 m distance 91 (79) // 103 (65) -
Numbers are for 90 degree hits, bracketed for 60 degrees.
KwK 36/L51 (Tiger I)
PzGr 39 8.8cm // PzGr 40 8.8cm
500 m distance 111 // 156
1000 m distance 100 // 140
1500 m distance 92 // 125
2000 m distance 84 // 110
Numbers are for 90 degree hits.
Note that the PzIV and Tiger II had different guns...