A bully expert is called a bullnation
An Expert Aviator is called an "Ace".
A cultures expert is called an ethnologist.
what ia an expert pilot called
The difficulty does not affect the weapon statistics.
Don't know the origin of the word, but a snake expert is called a herpetologist.
An expert on China is often referred to as a Sinologist or a China specialist.
An expert who provides opinions and advice in their field is typically referred to as a consultant or specialist.
A cultures expert is called an ethnologist.
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.
The study of earthquakes is called seismology so an earthquake expert should be called a seismologist.
A collection of weapons is an arsenal.