In North America many tribes during the 17th and 18th centuries had plentiful access to firearms due to European traders eager to get their hands on fur and other goods. With some amassing a significant amount of power thanks to guns and incorporating the weapons into their culture.

I sometimes hear this contrasted with central and south America where the Spanish government was able to keep a much tighter control over the arms trade. Just how effective were the Spanish at keeping european arms out of the hands of the natives and why were they apparently much better at it than European nations in North America?