I have researched smokeless powder and on top of that have researched magazine fed rifles. Thus Myself and my army are entirely equipped with modern bolt action rifles that are using "smokeless" powered ammunition, and there are still significant clouds of smoke emitted. No noticeable difference from prior to the research for older firearms

https://i.imgur.com/JO0xSeH.jpg


https://i.imgur.com/xtJ5wNw.png



Granted its technically not zero smoke, but the amount should be negligible amounts by the technologies own description within game relative to old blackpowder.