Check the shell latch, I have an AKKAR, that in US is sold also by CD, and it had the very same problem as yours, I asked for advice in a shotgun forum and most of the time the shell latch is rough, and hold the shell for just more time, the elevation missed the shell and it falls to the ground, try first to lube slightly the shell in the rear, if it feed properly, it's the feed latch rough.