This is kind of insane. Like as he notes it's still quite alpha level (and in the interview they discussed that it's quite a slow bullet at the moment, no method of rifling, and takes quite a few seconds to actually fire - so not military ready) but quite a bit more advanced than I'd have expected.
Also weird to see how much of it is 3D printed (and even using some parts - the twisty wheel on the top is exactly the same as I have on my 3D printer). Also he shows the bullets against regular bullets, but like while the size is comparable - it fires the whole bullet (hehehehehe) but regular bullets obviously don't shoot the jacket). And having watched a bunch of his videos, including some with misfires, and that is the silliest way of clearing a misfire he's ever done (just drop the bullet out the front).