This is what gets me the most. Just an 'official' brochure or a banner at one of the many Chinese military expositions would be more than enough of a confirmation. It is not as if I don't trust the 'big shrimps' like
@huitong, it's just that in this case, the caliber of the gun can be anywhere from 12.7 to 23mm IMO. I'm sure there is a pic somewhere of someone comparing the rounds of the Z-10 gun with other known caliber rounds and thus coming to a conclusion what caliber it is.
I understand there is secrecy surrounding military products, but such a relatively banal thing as the caliber of the gun on a decade plus old helicopter that is also offered for export, is overly cautious IMO.
This type of thing is not uncommon in China, it happens because of the bureaucracy. At least that is what I think...
Basically what happens is that there is a order of some type from higher ups (often sensible orders with good intention), and it is often executed in the stupidest way possible at a local level because local officials want to show that they are good at following orders or they do not want to take any risk at pissing people off in the higher ups. Regardless, these orders are being followed in a manner that totally misses the original intention and is too excessive, and everyone hates it, but you can't really say what they are doing is wrong. So you just get stuck in this stupid place forever unless the higher-ups discovers the shenanigan the local officials pulled off.
Take this military secret protection thing (保密), for example. I think no one disagrees that it is important to have guidelines in place about what can be shown and what cannot be shown to protect military secrets. But some local officers throw out the most basic common sense when complying with this rule and the end result is just plain stupid. Like in some military reports, they will blur out the QBZ-95-1 soldiers are holding (I saw this in a post couple of months ago, so I guess a PLA officers somewhere still thinks that showing this gun is a violation of 保密条例 and will compromise the integrity of PLA). Also in military news in CCTV7, they sometimes refer to 10 year old equipment as "some types of new equipment" (某新型战车,某新型飞机,某新型导弹)when everyone with the most basic military knowledge will know exactly what they are talking about because the news segment is literally showing the "some type of new equipment" in action...
You know, the recent leaked photos of 003 from tiktok is a pretty good example. A construction worker was able to film 003 under construction, and upload it to tiktok, when it is clearly against the rules. At the same time, the QBZ191 project was so well protected that no one even know what the thing looked like until the night before the national parade of 2019. Obviously some projects are a lot easier to be kept secretive than others, and I am not saying that the PLA is bad at protecting their own secrets, but I do want to point out that sometimes the way they handle information dissemination is just super weird...
anyways....
as for Z-10's gun, this video has some good footage
this also shows Z-10's cannon being reloaded