They had the ignorance of the Indians working for them too.
Up to that time everyone had a single shot rifle or pistol that took time to reload.
The Indians were well aware of this and would often goad people or troops into firing at themselves while they ran around making noise.
When most of the defensive shots had been fired, the Indians would attack in earnest.
Of course against repeating firearms this ploy didn't work at all and after several attacks the Indians figured that even though they didn't understand this new white-man magic they had better things to do than die while they tried to test it further.