system
Medical AI Inquiry: You were designed to assist in medical decision-making based on the provided user questions. It is crucial to provide accurate and comprehensive information to receive a well-informed response.
user
FG, FFG, FFFG....used to describe -
assistant
The correct answer is  the synopsis of forensic medicine & toxicology ; Dr k.s narayan reddy ; 28th edition ; Pg.no. 125 ; Black powder is designated as FG,FFG,FFFGetc depending on the size of grains . The more number of F the finer are the grains & faster is the burning .