Why no bronze or brass cannons?

[force200]

I noticed that all renaissance-era siege units require access to Iron in order to be built. However, a lot of historical cannons were made from bronze (especially earlier ones due to bronze being more flexible than iron and therefore making the gun less likely to explode) or sometimes even brass (especially for naval use, as certain types of brass are resistant to corrosion by seawater). Why the restriction?

 

[raxo2222]

I guess multiple modders were working on various things.

@Thunderbrd is going to unify units with his unit review projects.
This means requirements and stuff related to units will be much more reasonable.

 

[Thunderbrd]

I noticed that all renaissance-era siege units require access to Iron in order to be built. However, a lot of historical cannons were made from bronze (especially earlier ones due to bronze being more flexible than iron and therefore making the gun less likely to explode) or sometimes even brass (especially for naval use, as certain types of brass are resistant to corrosion by seawater). Why the restriction?

I recently noticed this as well when researching the materials to make cannons and included bronze as a possible metal for numerous cannon type units. Interesting you should bring it up as this was news to me at the time. This resource access portion of the unit design project is very slow going unfortunately.