I thought it would finally get fixed with the Elite Armour doctrine updates but it didn't so here i go
The description of veteran 4 reads:
"Battle hardened crews extend the range of thier main gun through the use of advancet targeting and sighting equipment."
So it should increase the range of the main gun, but it doesn't, it actually increases sight range by a bit instead as you see here:
So either change the description or add the increased main guns range. (I as an OKW main would prefer the second option )