Nades do not explode through walls. And in any case they are standard game items. The mod did not touch them. The same goes for semtex except the difference is that semtex cannot be cooked, has a shorter fuse, and of course it sticks. Chinalake has a radius of 256, like frags. But minmax damage is linear from 120 (instead of 300) at the center and 40 (instead of 70) at outer range. Exactly like it is for regular GL attachment.
So if this is an issue it is one with how the game decided to set the stats.
edit: I was very careful to make sure the Chinalake damage, radius, range and all that was exactly what it is for the GL attachment even tho BO chose to make it otherwise.