Reading the blurb about nuclear rounds, I've now come around to the thinking that it was correct originally. Nuclear rounds are TL6, only available for heavy weapons. The passage used to read
Now it reads
I think the original wording means that you can have bombs and artillery rounds at TL6, but nuclear grenades or LAG ammo appears at TL13 (nuclear machineguns will be off the menu because they can only use rifle special ammo). The new wording actually doesn't make sense, because it implies that the larger
nuclear rounds only become available at TL13, implying that you can get small nuclear rounds at TL6, which I don't think makes much sense.
Sorry - this is an edit that I instigated.