I would like to return again to the subject of the Dura Europos bolt.

Photo by, Yale University Art Gallery; and copied from, Greek and Roman Artillery 399BC-AD 363, by Duncan Campbell.

I quote myself from a previous posting:

“This artifact is the only intact specimen of a Roman ballista bolt ever discovered.  It was excavated in Dura Europos, Syria, and is likely the type of projectile used by the Orsova ballista. Bolts of this type must have been made in the tens of thousands by the Romans. The wooden shaft is made from ash and the quadrobate iron tip is a four sided square, designed to punch through shields, armour, clothing, etc.  The thinner foreshaft of the Dura Europos bolt was designed to aid penetration, it also raised the ballistic coefficient to aid in a long flat trajectory. The swelling at the rear of the bolt not only helped absorb the powerful thrust of the bowstring, but also acted as a kind of aerodynamic counter weight to help keep it steady in flight. This inherent stability was further aided by the short stubby fins.  These fins were made from maple and glued into grooves cut in the ash body.   Overall length is 18″, thickness at the rear end is 1  3/16″ and it tapers down to a bit over 1/2″ in the front.  It was reported to be a good deal shorter than the type of bolt that came before it.  Late style ballistas like the Orsova model did not have any kind of narrow opening around the bolt groove that the projectile would have to pass through.  (See earlier postings of Gallwey ballista.)  The arched strut on these later iron framed machines meant they were better suited to firing the shorter style bolts.  The danger with a short bolt is that if something goes wrong, and the bolt turns sideways during the power stroke, it will likely smash into the supports in the middle of the box frame.  With an arched frame the whole mess will be cast out the front, avoiding unpleasant ricochets and perforated catapultiers.”

Since writing that two and a half years ago,  I have experimented with several of these style bolts.  In my experience they all have one thing in common — without exception they all snapped in two a few inches back from the head on their first shot.   This feature, while no doubt appreciated by their originators as a simple precaution to prevent these projectiles from being fired back at them,  was not appreciated by yours truly who was trying to fire a long series of shots to build up data.  Consequently, I swore off Dura style bolts for general testing purposes, and resolved only to look at them again when the machine was finished.

I mention all of this because it is very nearly time to again pick up the trail of these elusive and fragile projectiles.   Because they seem to break no matter how carefully arranged the backstop is,  we might as well get some data out of them by experimenting with their penetrative capability.

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