4th Gen question about berries

[eternalglory]

ive been searching the internets, but i cant find the answer to my question: How much do berries that lower a super-effective move's effectiveness lower the... effectiveness?

 

[Gymnotide]

Alot, I would think, but I don't know specifically.

I can just tell you that Ice Fang would have OHKOed
Gliscor, but it only ended up taking ~30%.

 

[airconditioning]

Alot, I would think, but I don't know specifically.

I can just tell you that Ice Fang would have OHKOed
Gliscor, but it only ended up taking ~30%.

I think it cuts the damage in half.

Just so you know, Ice Fang has 65 Base Power, and Gliscor has 125 Base Def. Even with a 4x weakness, something like that wouldn't OHKO. And hey, Mantine can survive a Thunderbolt.