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There're some reasons and cause hopup damage, first check on magazine feedlips is in the right shape, if encountered the gap too large (resistence of feeding become smaller) or double bb's jammed between the lips that will squeese and cracke the hopup base; also recommend use better quality brand bbs and don't fill gas over 6 seconds and over 40 rounds. (50 rounds for plastic magazine)
[ Warning ] The quality of BB: This is very, very, very important. Please do not use poor quality one (soft BB, environmental BB, very cheap BB...etc.) Most of hop-up damage case is result of it (I am pretty sure that more than 90% players say good-bye to their hop-up is for this reason...). Those kind of BB will stuck and squeeze in hop-up when shooting, and then crack your chamber.