I'm using 4turns/year, and I've divided all the dates in descr_events by 4, so that they still occur on roughly the same turn as it would on 1turn/year. I've played two different campaigns, with the first reaching turn 241, and the second reaching turn 272. At these stages, of the powder units available, I can only recruit siege weapons and hand gunners.

Spoiler Alert, click show to read: 
This is the descr_event file I had for the previous campaigns. Multiply each date by 4 to get the equivalent turn where they are discovered/available (for 4turns/year). So Flintlock is discovered on turn 200.

event historic musket_invented
date 37

event historic first_watch
date 39

event historic pike_and_shot
date 40

event historic the_wheellock
date 42

event historic ADVANCED_METALLURGY
date 44

event historic ADV_MATCHLOCK
date 46

event historic the_flintlock
date 50


I figured there must have been a problem with my install, so I uninstalled and deleted all the files, and did a clean install again. Although this time I set every date in descr_events to 0, so that every unit and building should be available at the start, but it's the same as before. I can still only recruit powder siege weapons and hand gunners. I tested it with multiple different factions: France, Venice, Aragon, Genoa, and a few more that field a variety of powder units, I used cheats to boost population and give myself gold to fully upgrade cities/castles, so the should be available, yet they're not.

Is there something else I'm missing? Has anyone else had this problem?