[MaciekA]

I'm not sure what hopup units in a DG look like but a common test I do before firing an AEG after building it is to take the hopup unit + barrel, and manually feed a BB into the hopup chamber. I then take a knitting needle or narrow driver or whatever and VERY GENTLY tap the BB. If it doesn't go past the bucking, that's a smell. I try tapping harder, and if it requires a lot of force to push through, that's a guaranteed jam.

If a DG is able to do this test, you should do it. Maybe it's just as easy as replacing a bucking.