Does anybody shoot a Howa 1500 in 223 and 20" Heavy barrel? They have a 1-12" twist. How do they shoot 69 grain Sierra Matchkings or Lapua Scenar or 70gr Berger VLD's ? Is this easy to do or is it better to stick with 50-62 grain bullets. The max distance on the range is 400 metres. Are these heavy bullets that much better on windy days ?