Primer for a KV-1 tank model

The majority of Soviet armour in W.W.II was a dark green colour. What lighter colour are you planning on painting this kit? If you are doing a winter whitewash scheme then you would still use a basecoat of dark green before applying the white.

Miller41 - for armor I usually use a flat, light gray primer. Virtually all military colors cover very well over this. Two very light color coats are usually all that's necessary.
The two colors I use most are Model Master 1728 (light ghost gray) or Tamiya XF-66 (light grey). They cover well and accept other paint very well.
The light gray will cover the dark green plastic very well, so you shouldn't have any problems with the cololr coat.
Cheers,
LeeTree

yup, winter colors. Thanks for the help, these forums are a godsend:-)