"He thinks of weapons made of iron as if they were weapons made of straw." Straw would not get through his hide, and iron weapons do not get through his hide. (See: [[rc://en/ta/man/translate/figs-simile]])
You can make this clear by adding the omitted words. Alternate translation: "he thinks of weapons made of bronze as if they were weapons made of rotten wood" (See: [[rc://en/ta/man/translate/figs-ellipsis]] and [[rc://en/ta/man/translate/figs-simile]])