BZ-75 (tier X)
- The maximum forward speed has been changed from 35 to 30 km/h.
- Gun dispersion changed from 0.4 to 0.42 m.
- Gun reload time changed from 17 to 18 s.
- Gun aiming time changed from 2.7 to 2.9 s.
BZ-68 (tier IX)
- Durability with BZ-68 turret changed from 1850 to 1800 HP
- Durability with BZ-68-1 turret changed from 1950 to 1900 HP
- The maximum forward speed has been changed from 35 to 30 km/h.
- Changed the reload time of the 130 mm M-65 Type 70 gun in the BZ-68 turret from 15.5 to 16 s.
- Changed the aiming time of the 130 mm M-65 Type 70 gun in the BZ-68 turret from 3.1 to 3.2 s.
- Changed the reload time of the 130 mm M-65 Type 70 gun in the BZ-68-1 turret from 15 to 15.5 s.
- Changed the aiming time of the 130 mm M-65 Type 70 gun in the BZ-68-1 turret from 2.9 to 3 s.
BZ-166 (tier VIII)
- Durability with BZ-166 turret changed from 1500 to 1450 HP
- Durability with BZ-166-1 turret changed from 1550 to 1500 HP
- The maximum forward speed has been changed from 35 to 30 km/h.
- Dispersion of the 122 mm Type-59-2 gun changed from 0.42 to 0.44 m.
- Changed the reload time of the 122 mm Type-59-2 gun in the BZ-166 turret from 13.8 to 16 s.
- Changed the reload time of the 122 mm Type-59-2 gun in the BZ-166-1 turret from 13.5 to 15.5 s.
BZ-58 (tier VII)
- The maximum forward speed has been changed from 35 to 30 km/h.
- Changed the aiming time of the 85 mm Type 58 gun from 2.3 to 2.5 s.
- Dispersion of the 85 mm Type 58 gun changed from 0.36 to 0.38 m.
- Changed the reload time of the 100 mm Type 59M gun in the BZ-58 turret from 11 to 13 s.
- Changed the reload time of the 100 mm Type 59M gun in the BZ-58-1 turret from 10.5 to 12.5 s.
Source: Russian WoT page, https://tanki.su/ru/news/updates/1-19-1-PT-2/
EU hasn't updated the page yet, but the 2nd iteration of CT is already up. Here's the BZ-75 with its nerfed gun:
https://preview.redd.it/6x9ty43mcg7a1.png?width=1246&format=png&auto=webp&s=39787406f57e5de0005d7920b4dd4b7649aa94e5
Derp guns aren't still back and presumably no changes to the armor layout or soft stats, so these are all pure nerfs.