from the looks of the videos the LRBHO is much more important for reload rate compared with whether you use the button release or the AK mag release. From looking at the rifle it seems that the QBZ191 doesn't have this function again, at least I can't see a bolt release button. I guess PLA still subscribes to the idea that fewer moving parts = more reliable weapon... 1 fewer spot for dust to get into/fail/jam
Speaking of mag releases though it looks like the rifle that lost the competition did have mag release button and kind of follows the NATO AR pattern for reloading.
I am not sure you are correct that the QBZ191 doesn’t have the bolt hold open and release function, from the video provided by By78 and other videos, the bolt clearly holds open after the last round and from the images of the left side of the weapon suggests the latch/button just above the mag well is the bolt release mechanism.
Prototypes of full-length and carbine versions.
Two even higher-resolution versions of Bltizo's recently shared images, with links to their full-resolutions versions.
Here's the video, albeit only 480p.
If you look at the video at 4:02 after the ejection of the round and from the angle although not clear the mag seems empty and bolt does not close and can be seen being held back and open.
Then from this video another test of the rifle, note at 1:33, if you slow the video playback the bolt is held open and from the action of the tester during the removal of the empty mag suggests that he is using the latch just behind the mag that rests on the trigger guard, tho this is not entirely clear.
Whilst it’s not conclusive as we never see the bolt release in any videos, at least of the ones I have seen, it’s enough to suggest there is a bolt hold open and a release mechanism and the most likely candidate for the release mechanism is the button on the left side of the weapon, this button is also at the seam that separates the upper and lower receiver, so it seems to LRBHO you were referring to.
Having said all that, this is only my guess, since there is simply not enough information to prove it. If all this have been said before then apologies and mods please remove.
A7368412-B858-4D5D-B1EE-006EC37A1A7F.png
