Weapon accuracy...mechanics?

The weapon accuracy I am talking about here would have to do with a weapon such as the chaingun, or, in vehicles, the smaller gun on the tank or the weapons on the Shrike.

I bring up Tribes 2 examples becuase I can remember one of the numbers used. I seem to recall one of the last patches changing the "accuracy spread" of the Shrike's weapons to 8 percent.

At least I think it was a percentage.

Can someone illuminate this lowly designer in the ways of "accuracy spread", at least as Tribes 2 addressed the issue?