[5e] Bronze Age D&D: Rules for low tech weapons

Metalworking was considered more akin to magic than technology for much of its history. During the early Bronze Age, you had cultures that were still chipping axes and clubs out of flint living alongside cultures that had mastered smelting, casting, and other complex techniques of metal work. Supplies of important ores were highly localized and trade was slow and dangerous.

Krynn, the setting for the Dragonlance books and game modules, is one example of a campaign world where metal scarcity was an issue. Athas, the Dark Sun setting, was another. Both games had rules to deal with metal scarcity- Krynn replaced gold with steel as the most valuable currency in the world, and 2nd edition Dark Sun had rules for stone, bone, and obsidian weapons. Telling players what metals weapons are made from can add color and detail to the game world. It can also reflect cultural differences in game- maybe a remote island has plenty of tin and copper, but no iron ore. Maybe the local tribe of hobgoblins has learned the smelting and casting of bronze, but has been denied access to more advanced metalworking technology (which they would happily kill to acquire).

Making antagonist weapons bronze or other inferior materials can also discourage players from hoarding the gear of fallen foes, if you'd rather not bother with encumbrance rules. By the same token, a player who loses their primary weapon and has to survive using an inferior one taken from a fallen foe or enemy weapon store can make for some interesting drama.

Rules for Bronze Age-style Weapons

Default weapons are bronze. On a critical failure (rolled a 1 when rolling without disadvantage), the weapon is damaged. Attack rolls are made at disadvantage, and damage becomes 1d3. This penalty persists until the weapon is repaired by a metal smith, requiring access to a forge, anvil, and metal working tools. If the weapon is damaged again before it is repaired, it is destroyed.

Masterwork weapons (double cost) are made of iron and are not subject to breakage.

+1, +2, +3 weapons are made of steel and not prone to breakage.

Iron and steel weapons must be sharpened regularly to retain any bonus to hit and damage. This is assumed to be done during short or long rests, provided you have a whetstone. Bronze weapons rely more on weight and geometry than on a fine edge, and so don't need regular maintenance.