xEclipseX wrote:
100%

That is incorrect. There is no specific chance that we know of. It isn't random, every weapon has a certain probability of failing and passing. Also each plus has a failure/pass rate. Some weapons go from +1 to +9 no astral or immortal, only lucky powder and elixirs 9 times. Other weapons require over 30 elixirs and lucky powder to get just +3.