Why were they all subdued in the 1800s ?
Our big issue wasn't guns. It was the industrial revolution. White people's discovery of Better methods of refining explosive chemicals, big steel industries, development of industrial supply chains, and learning trade secrets of manufacturing processes made existing weaponry much much much more lethal.
It's actually not that hard to stop muskets or primitive shot guns in guerilla warfare . While Africans specifically had access to guns through trading or theft, a lot of the native Americans were able to fight guns with arrows because they had a higher reload rate and better accuracy. But no matter how well you were organized, or how many mountains , woods, Jungles or swamps you had to hide behind , it wasn't going to stop and artillery shell from a mile away or high caliber machine guns.
The issue arises When you need a huge national industrial engine to start creating things like artillery or machine guns. Even if you were to loot these materials from defeated soldiers, sourcing artillery rounds or complicated ammo for machine guns would be very difficult. The game is over the minute a machine gun enters the battle field.
Personally, I would credit the British engineer William Armstrong with single-handedly ending Resistance movements for most indigenous people against Europe. His ability to mechanize death in the mid 1800s was catastrophic.
The effect of the industrial revolution is to the extent that if the Haitian revolution were to occur in 1860 instead of 1806, Then all The revolutionaries would have been massacred.