Hmm...I get 27-1/2" on mine.
I was always under the impression that the original prop was a real crossbow of the time, possibly a European tournament crossbow.
When I saw the Horton Magnum being used to scratchbuild props I immediately concluded that Horton acquired the original design either through a defunct company or it was an old design of theirs. Then they retooled it for injection molding in whatever space-age material they used. In the retooling process, they made certain modificatoins, the most noteable being that they filled in the negative space from the origilnal design.
This would provide more stability with the lighter material and add some weight, perhaps helping to balance the weapon. I suspect that it would make the manufacturing process a bit easier as well.
So...let's not assume that they actually used the current Horton Magnum for Chewie's crossbow. It could have been an earlier productoin piece from Horton or another company. It could have been a prototype. It could have been a specialty crossbow for tournament use only and not marketed to the general public.
And yes, it could have been that blasted Champaigne crossbow.
Whatever the case, I'm sure the bow used for Chewie's prop was original to the weapon they used. We're just trying to find a suitable replacement for the Horton Magnum, which is roughly similar in shape, but doesn't have those neat 70's swooping curves. So far I haven't found any source for just the bow, which is called the prod in crossbow circles.
Not trying to rant here, just trying to offer some perspective and help uncross some wires.
BTW, those pics - is that TK818? I've been trying to contact him with no success.
Patrick