Are you speaking of Bunker doubles vs. ATA doubles.. both very similar.. But.. bunker singles to ATA doubles.. Bunker has a very flat target.. fondly?? called the grasscutter.. It's a 76 meter target that is almost dead flat.. A high shooting POI will hurt you on that target.. Anything over say 60/40 would be the wrong way to go.. You will get about 4/5 of them in every 25 shots..so you can quickly see why most bunker shoioters shoot a pretty flat rib.... As always.. to each his own..