On a recent gaming trip to Scotland, Dave ("from the podcast") and I dropped into the Roman Army Museum, which is near the Vindolanda fort and is part of the same group of museums allowing entry with a single ticket.
There's a fair bit of stuff to go through from this trip, most if not all of which will make it to this site eventually - but I thought these reconstructued ballistae were pretty interesting in wargaming terms, mainly due to their (small) size.
The one on the left is apparently a millimeter-perfect reconstruction based on an actual ballista frame discovered at Xanten-Wardt in North West Germany in 1999 - and it is very clearly man-portable and designed to fold up, to the extent that you could almost imagine Roman soldiers using it in pairs with one offering his shoudler as a tripod as if they were a WW2 German MG34 team!
Looking at how small and delicate the real thing looks however, I started to wonder if a 15mm sculptor and caster might struggle to make something with these proportions - the legs look almost too spindly to confidently reproduce in metal at that scale for starters - so instead might end up designing and casting a bigger, cruder version that actually works on the tabletop without breaking at first contact with a wargamers thumb and forefinger.
So, taking this train of thought further, are our wargamers mental images of tactical ballistae are in fact much bigger than they actually were because of the technical limits of 20th Century spin-casting technology - not the limits of 1st Century wood and metalworking?
In terms of a "mass battle" of many thousands that we wargamers often simulate the effect of this still may not have been all that significant, but walking through the countryside near Hadrians Wall, and seeing the size of the garrison at Vindolanda you can easily imagine that the norm would have been much smaller actions - where a sustained volley of well-aimed long range bolts may indeed have had a quite dramatic effect on the morale of a tribal warband numbering in the dozens, rather than the tens of thousands.
So, some idle speculation to accompany these pictures of torsion artillery - but, even if its nonsense it did make me think, and make me also realise that no matter how well read you may be, it's still always useful to get out there and walk the course occasionally!