As an English Language teacher specialising in English as a Foreign Language for the first 20 years of my career, the question of Standard English often cropped up. There are number of standardised versions of English, each with their own particular vocabularies and grammar structures. Standard British English and Standard American English differ in both vocabulary and grammar.
If asked this question by one of my students, my answer would be that the topic being discussed is one specific to a certain interest group or profession and therefore the terminology used within that closed group falls under the register of that limited speech community.
It appears that the term 'water table' is commonly used by American members of the community in question. It is not used in British English. The term 'Action Flats' is used instead.
The term 'gas' in British English means natural gas, in American English it means (in British English) petrol, which is a liquid, but the term as used in American English is a contraction of 'gasoline'.
The short answer is that if discussing guns in America, with Americans the 'water table' term is going to be used commonly. If in England, it will not be heard. There is no 'right or 'wrong' in this case, simply that the different words emanate from different places, where they have gained common currency.
Last edited by Small Bore; 02/04/14 06:57 AM.