Great work! Just some suggestions here
The Thompson 7.62mm conversion in the photo is a post-war (post-civil war even…) conversion, so it does not fit the time frame of the game.
The best br2 Thompson candidate is still the Sichuan Arsenal 7.63mm Thompson, these guns can use bayonets instead of bipods if you don’t want them to be exactly the same.
The Mukden SMG is a tricky one because we don’t know exactly when they were made, some theories suggest they were made after WW2 using captured Japanese Type 1 SMG production lines and parts in Mukden. While others suggest they could be made during WW2 by smaller gun workshops, similar to the Sichuan SMGs. The designs shown on the surviving examples of Mukdens vary A LOT, some of them show design elements from Thompson, which were popular among those small-scale productions. Also, the Chinese collaborators of imperial Japan were notorious for stealing and selling Japanese industrial materials, weapon parts, supplies, etc. Which could explain some Type 1 elements on the gun.
The type 67 grenade is also a post-war model… the WW2 versions of Stielhandgranate were simply called Bingshi (means handle grenade) or Type (insert_factory_name_here) grenade, the most common being Type Gong. Stielhandgranate produced by different factories (under different warlords’ control) has small differences in size, material, and explosive mix, therefore the second naming method was sometimes used.
They also use a type of impact grenade called Mawei (horsetail)
Tsing Dao Type 17, and other SMGs based on Bergmann’s design made by the Chinese, all use 7.63mm Mauser ammunition and usually use either 30-round or 50-round mags. (the 50-round mag was also quite common)
So similar to SIG 1920, this type of gun can also be BR3 when using 50-round mags.
9mm Para MP-28 was only exported to China in very small quantities, some used by the German-trained divisions of the NRA.
The Type 14 rifles… I think you mean Type 1 and Type 4 rifles? Those were not called Zhongzheng though, Type Zhongzheng is just what the Chinese call the Type 24 Chiang Kai-shek Rifles.
As for the rifle grenades, as far as I know, the Chinese do not have AT rifle grenades for the Type 28 launcher. However, there is a type of white phosphorus rifle grenade used by the Chinese, that could be an interesting addition to the game.
As for the “copy-paste” guns, ZB-26 is definitely an iconic choice, Chinese also use a variant with a light tripod and 30-round mag, which could also be added to the game.
For the BR3, I think KE7 is a better choice, it’s more common compared to DP. There can be some small differences in detail comparing to the one on the Japanese tech tree (Which represents the ones exported to Japan for testing I guess) Those made by or exported to the Chinese were chambered in 7.92 Mauser. Also, the ones made by Sichuan Arsenal use MP18-style barrel jackets.
