1) There are multiple Qin crossbow findings with powerstroke above 20 inches. Historian Yang Hong in Weapons in Ancient China states that the Qin crossbows (plural) found in Qin Shihuang's tomb had stock lengths of around 71.6 cm. Later findings of Qin crossbows after the book was published were also around the length. At least some of the Qin crossbows were foot drawn.
2) from the records of Wu and Yue, every stone of draw weight requires an increase in arrow weight, so that a six stone crossbow would be shooting a 93.75 gram arrow. This wouldn't make sense if powerstroke is decreasing with draw weight increasing.
3) the amount of military crossbows found are mostly of long powerstroke compared to medieval european ones, except mostly mechanically drawn repeating ones. The Chu-Yen slips also show most crossbows to be of six stone draw weight. If what the number implies don't reflect reality, then this is an astronomical coincidence.
4) the song shi shows that their ShenBiNu crossbow had a stock as long as a meter, and draw weight as heavy as 300 lbs. I will dig up the quote when I'm back to my laptop.
Do you have a single primary source showing that high draw weight crossbows invariably have low powerstroke for ancient to medieval Chinese crossbows?a single primary source stating both the powestroke and the draw weight being of a certain measure while talking about the same said crossbow.
1) How do you know Roman torsions pack a hell of a punch, are there primary sources showing both their draw strength and powerstroke?There is basically no data for the manuballistas, only estimates and mist selling.
Draw weights go from 150lbs to 1500lbs, the powerstroke varies wildly depending on how long the bow arms are estimated(considering the torsion mechanism moves the arms backwards instead of flexing them, increasing the powerstroke a bit more) and the energy delivery effectiveness of the torsion mechanism itself estimated from as low as 20% to 50-60% without anything to back it up but opinions.
2) Roman torsions weapons can be both outswinging and inswinging. Some finds show that they can NOT outswing because the arms would smack against the frame. Also, how do you know the arm length of Roman torsions machines?
3) calculations of 20 percent efficiency for Roman torsions ballista can be derived from replicas. Meaning it is no longer a guess, as long as you consider that the sinew bundles are not sinew.
If you are talking about who I think you are talking about, the guy changed his mind and now believes ancient to medieval Chinese crossbows can have both high draw strength and long powerstroke. This is done by showing him Euler's compression formula and a windlass crossbow just prior to the string being cocked, because during this point the stress of a ton of draw weight is distributed along the entirety of the long stock, not just up to the trigger.Absolutely, the powestroke being long is not the issue.
The issue argued here is merely the powerstroke staying long with heavier draw weights, which is something a lot of people do not believe, including a number of Chinese historiographers which I will quote the moment I manage to find the article I read a year ago about the topic of post-Han crossbows until the Tang.
I do not argue at all that the Chinese crossbows were the most powerful hand held projectile weapon until the invention of the firearm, I merely doubt the powerstroke of the heavy draw pieces somehow being so long in the early dynasties then suddenly being shortened for some reason the moment we actually do get data on the heavy draw weight pieces.
Suspicious, that's all.
Also my thread that I linked to also explains the short powerstroke of Ming crossbows. Did you read it? The Han crossbow is built with a sniper rifle mindset. The Ming crossbow is built with a pistol mindset. It's not fair to say the pistol is inferior to the sniper rifle on the basis of shooting power, because the pistol is built for compactness in mind. The Ming crossbow is very tiny compared to both the ancient and Medieval Chinese crossbow and the Medieval European crossbow.