I'm pretty sure that at 1500 meters, Panthers had a 5% hit rate first shot. And not going to go all "GERMANY UBER ALLES" crap here, but I think its genuinely accepted the German long 75 had better ballistics than the Soviet 85mm
It's not really a problem of balistic, but of optics. The Soviet guns were renowned for their external balistic (after the shell exit the gun), while the germans were renowned for their internal balistic (inside the gun). Look at all the excellent artillery guns they built (ZiS-3, the famous ML-20 152 mm, etc.). Some of them were even loved by the Germans! The optics were the real soviet problem because it needs a very quality oriented industry, something the Soviets weren't ready to have. The Soviet WWII optics weren't very good, particularly before 1943. However I remember reading that after that, the Soviet started to copy captured german optics (and Soviets were expert at reverse engineering). Probably that the industrial quality was lower however.