Wei Yuan Pao (威遠砲)

UPDATED APRIL 17, 2026

Illustration of a large (left) and small (right) Wei Yuan Pao, from 'Wu Bei Zhi (《武備志》)'

The Wei Yuan Pao (威遠砲, lit. "Awe-inspiring long range cannon") was essentially a stripped-down version of the wrought-iron Da Jiang Jun Pao (大將軍砲), developed during the late Ming period, probably around 1600. It discarded the cumbersome reinforcing hoops of the Great General Cannon, as it became clear through experience that the latter's advanced wrought-iron construction was already significantly overbuilt for the required size, weight, and firepower, making the reinforcing hoops unnecessary dead weight that only hindered handling and mobility.

The Wei Yuan Pao retained the general profile of the Great General Cannon, including the flared foot for vertical cleaning and reloading and abacus bead-shaped powder chamber. Unlike its predecessor, however, it featured a slightly flared muzzle, an iron sight similar to that of matchlock gun, and a touch hole lid similar to the type commonly found on Shen Qiang (神鎗).

A Wei Yuan Pao in the China Great Wall Museum, Badaling, China. Note the absence of reinforcing hoops. Source: Zhihu.

According to late Ming military treatise Li Qi Jie (《利器解》), the Wei Yuan Pao was produced in two sizes. The lighter version measured approximately 2 chi 8 cun (90 cm) in length and weighed 120 jin (71 kg), with a bore diameter of roughly 2 cun 2 fen (7 cm) at the muzzle and a bore length of 2 chi 3 cun (74 cm), giving a rough calibre (bore length to bore diameter ratio) of about 10.5. It was loaded with 8 liang (296 g) of gunpowder and fired a large iron-cored lead ball weighing 3 jin 6 liang (2 kg or 4.6 lb) along with one hundred 6 qian (22 g) lead bullets. Due to its light weight, it could be easily carried by a horse or mule. 

The heavier variant followed the same general proportions for length, bore length, and calibre, but was scaled up in weight to 200 jin (118 kg), with an estimated bore diameter of approximately 2.6–2.7 cun (8.3–8.6 cm). It was loaded with 1 jin (590 g) of gunpowder and fired a 6 jin (3.5 kg or 7.8 lb) iron-cored lead ball.

While other contemporary Ming military texts record slight variations in these dimensions and specifications, some recommending a powder charge of up to 1 jin 4 liang (740 g) for the lighter version — a remarkably heavy charge for such a light piece, made possible only by its robust wrought-iron construction — the general characteristics of the Wei Yuan Pao remained fairly consistent across sources.