Midcap Syndrome in Super-Slow-Motion

This slow-motion footage of a nozzle pushing a BB into the barrel shows how and why the midcap syndrome occurs.
As the magazine pushes the BBs into the chamber, and the chamber ceiling is a bit too high, the second BB gets a little on the way of the nozzle. While pushing the first BB into the barrel, the nozzle has to push the other BBs back into the magazine a bit, so it could pass them. The stronger the magazine spring pushes (the fuller the magazine), the harder it is for the nozzle to push the BB into the barrel in time. Eventually the piston has already started traveling forward, before the nozzle has sealed the barrel.
This problem is solved by shortening the tappet plate spring by 2-3 coils, and is more likely to occur with nozzles with the flat forehead, rather than with the tapered ones. However, the real cause of the problem is the chamber ceiling being too high.