Here's the info I have on grenades:
I wouldn't pay too much attention to the effective radius (as it's from different sources) other than to note the already understood difference between offensive and defensive grenades, and that the Soviet F-1 was poor quality.
Defensive grenades should have a higher HEK with no PEN
Offensive grenades should have a lower HEK with 1 PEN
If the designers went with generic grenades, then perhaps they should all get something like HEK 5 PEN 1
Cross