An Expert Aviator is called an "Ace".
A bully expert is called a bullnation
A cultures expert is called an ethnologist.
what ia an expert pilot called
A grammar expert is called a grammatician or a grammarian.
The difficulty does not affect the weapon statistics.
Expert advice or expert guidance.
An expert in his field is often called a specialist or an authority.
an expert on China is called a sinologist.
A cultures expert is called an ethnologist.
Don't know the origin of the word, but a snake expert is called a herpetologist.
Weapons qualification in the US Army has three awards. Expert, Sharpshooter & Marksman (the lowest of the three). The marksman award is sometimes refered to as the "BOLO Badge". For the standard personal arms--rifles and pistols--Expert, Sharpshooter and Marksman are the awards. For other weapons, like machineguns and grenades, they use First Class, Second Class and Third Class.