Building a Song Dynasty Fire Lance — The World's First Gunpowder Weapon

Select a thick-walled bamboo culm at least 3-5 years old, with an internal diameter of 4-5 cm and walls at least 8 mm thick. Cut a section 30-40 cm long, keeping one natural node intact at the rear end — this node acts as a natural seal, containing the explosion. The open end will be the muzzle.

Scrape the interior smooth with a knife or chisel to remove any internal membrane. The smoother the bore, the more efficiently the gas jet will exit. Sand the exterior lightly and check for cracks — any split bamboo will burst catastrophically when the charge ignites. Discard any tube with visible fractures or insect damage.

Prepare black powder in the Song dynasty ratio: approximately 75% saltpeter (potassium nitrate), 15% charcoal (willow charcoal preferred for fine grain), and 10% sulfur, all by weight. Each ingredient must be ground separately to a fine powder using a stone mortar and pestle — never grind them together, as friction can cause ignition.

Once individually powdered, combine the three ingredients in a ceramic or wooden bowl (never metal — sparks). Mix thoroughly by gently turning with a wooden spatula. The Wujing Zongyao specifies that the powder should be as fine as flour. You will need approximately 50-80 grams of finished powder for a standard fire lance charge.

Song dynasty fire lances used a mixture of iron filings and broken pottery shards as shrapnel — these were propelled out of the tube along with the flame jet, causing wounds at a distance. Collect clean iron filings from blacksmith work or file them from scrap iron. Break fired pottery into small sharp fragments no larger than a fingernail.

Mix approximately 30 grams of iron filings with 20 grams of pottery shards. The iron provides mass and penetration; the pottery fragments spread the damage pattern. Some variants described in the Wujing Zongyao also included small pebbles or fragments of broken arrowheads.

With the bamboo tube standing upright (sealed node end down), pour a layer of black powder into the tube — approximately half the charge (35-40 grams). Tamp it down gently with a wooden dowel. Never use metal tools for tamping — a single spark will ignite the powder.

Add the shrapnel mixture on top of the first powder layer. Then pour the remaining black powder on top of the shrapnel. This layering ensures the shrapnel is propelled by the expanding gases rather than settling to the bottom. Leave approximately 5 cm of empty space at the muzzle end to allow the gases to accelerate before exiting.

Drill or bore a small hole (3-4 mm diameter) through the bamboo wall near the sealed rear end, about 2 cm from the node. Thread a slow-match fuse through this hole so it contacts the black powder inside. The fuse is made from hemp cord soaked in a saltpeter solution (approximately 50 grams of saltpeter dissolved in 200 ml of water) and dried — this creates a cord that burns slowly and reliably at about 1 cm per 10 seconds.

Leave approximately 15-20 cm of fuse protruding from the outside of the tube. This gives the soldier 15-20 seconds to position the weapon before the charge ignites. Seal around the fuse hole with clay or pine resin to prevent gas leakage.

Roll several layers of thick paper or cloth into a tight wad and press it into the muzzle end of the tube. This wadding serves two purposes: it keeps the powder and shrapnel from falling out during handling, and it creates a temporary seal that builds gas pressure before the charge blows through it — increasing the velocity and range of the flame jet.

The wadding should be tight enough to stay in place when the lance is tilted or swung, but not so compressed that it becomes a dangerous obstruction. Song dynasty soldiers used mulberry bark paper (the same material used for early Chinese paper money) or strips of silk cloth.

Select a straight hardwood shaft approximately 2 meters long and 3-4 cm in diameter — ash, oak, or bamboo pole all work. The fire lance tube is bound to the tip of the shaft with the muzzle pointing forward, aligned with the spear's axis. Wrap wet rawhide strips or hemp cord soaked in animal glue tightly around the junction, overlapping in a spiral pattern for at least 15 cm.

The binding must be tight enough that the tube does not shift during use, but it should not compress the bamboo — any crack created by over-tightening will cause the tube to burst sideways when the charge fires. As the rawhide dries, it shrinks and tightens further, creating an extremely secure bond.

Black powder is hygroscopic — it absorbs moisture from the air and becomes useless when damp. Coat the entire bamboo tube and all bindings with a layer of tung oil or pine resin lacquer. Apply two coats, allowing the first to dry completely before applying the second. Pay special attention to the fuse hole seal and the muzzle wadding.

Song dynasty records indicate that fire lances were stored in oiled silk bags to protect them from rain. A wet fire lance was worse than no weapon at all — a misfired charge could burst the tube in the soldier's hands.

Secure the completed fire lance in a fixed position aimed at an open, non-flammable target area — a dirt bank or stone wall at least 10 meters away. Clear all combustible materials from a 5-meter radius around the firing position. Ensure no people or animals are within the danger zone.

Light the fuse at its tip using a slow-burning ember or candle. Retreat immediately to a safe distance of at least 10 meters. The fuse will burn for 15-20 seconds before reaching the charge. When it fires, a jet of flame and sparks will erupt from the muzzle for approximately 3-5 seconds, accompanied by a loud roar and dense smoke.

A successful fire lance produces a visible flame jet of 3-5 meters in length. The shrapnel will embed in soft targets within 5-8 meters. The bamboo tube is single-use — inspect it after firing and discard it, as the structure is compromised by the internal explosion.