This armour was designed to be a full-body "bulletproof" suit, only capable of stopping bullets from military assault rifles that have the same capabilities of today's ones. Of course, the design has a big part on this question, so let's say they work like deep dive suits, which use something akin to those "three bearing swivel nozzle" mechanisms as an articulation.
Not because these (today's assault rifles) will be exactly the weapons of this history's scenario, but because I believe it will facilitate the question. It is easier to asnwer using something that is real than something that isn't. And I "just" need to change a few things from the answer to fit in the history.
In this scenario they are build to withstand even 50 cal, but you don't need to actually use this as a base to your answer if you don't want. And again, it is easier to think/answer using real world bulletproof materials to base your answer on.
Its weight and other things aren't a big concern for this question, but if you include these, no problem.
So, the problem/question:
So, The articulations/joints/bearings wouldn't be as thick as in the image of the deep dive suit, but my biggest concern is how "pierceable" these bearings would be in an actual gun fight.
So, using conventional ceramic/metal bulletproof plate materials (in the same thickness or not), how well bullets would be able to just go through these joints?
I searched about tank armor and its vulnerabilities, like when two armor plates connects in different angles, because I thought it would be useful for this matter, but I couldn't find results.
(Of course, some shots would eventually distort the plate/joints and the rotary mechanism would fail, but that's not my concern because of some reasons that doesn't matter to this question.)