Interesting conversation, especially for an old artillery buff like myself.

I posted this before about trebuchets, but it is worth repeating.

In reality trebuchets were probably the most accurate seige engine of all and that includes most of the the primitive smooth bore artillery. While its range was limited to about 300 yards, unlike other primitive artillery, the trebuchet's propelling energy relied on the absolute constant of the force of gravity. Unless one changed the position of the engine, the length of the throwing arm, the fulcrum position, or the size of the counterweight---a trebuchet would put a projectile of uniform size and weight in the same spot just about every time.

All of the other pre-gunpowder siege engines such as the catapult, onager, or ballista relied on tension as a propelling force and this was subject to the varibles of the strength, quality, and condition of the tortion material used.

Early smoothbore black powder weapons also suffered from many variables including weather conditions, the inconsistancies of barrel manufacture, and the extreme variables of the quality of the gunpowder used.

Cheers