I recall a UK history documentary about German small arms and why it handicapped their armies. The Stg44 was hampered by very high scrap rates for the receiver stamping. It was around half the production. I don’t recall the particulars, whether it was the low quality steel they were forced to use, or the heat treatment of the sheet metal, which was the problem with the ak.
In any event, the round count an stg was expected to last was rather low with cracking putting the guns out of action.