What determines how many times moves such as doubleslap, fury attack, etc., will hit? This is probably totally unrelated, but it always hits me more just when I wish it wouldn't... XD
It's completely random unless the user has the Ability Skill Link then it always hits 5 times.
From Generation V onwards these are the percentages a multi-strike move has a chance to hit 2-5 times:
2 times- 33.3%
3 times- 33.3%
4 times- 16.7%
5 times- 16.7%
Sources: Here and here.
Hope I helped :)
As far as I'm concerned and can find out it is completely random, what ever random number your DS can think up between 2-5. However I have discovered some percentages on how likely it is to strike...
(Note these are Gen V and VI only)
2 hits = 33.3%
3 hits = 33.3%
4 hits = 16.7%
5 hits = 16.7%
Its luck really, to dodge the multistrike moves just get a fast Pokémon! x3
Hope I Helped! =]
Source and plenty of info on multistrike moves