but as Paul points out it couldn't be done from level ground, according to his understanding of the carriage construction. This indicates one of two things to me. Either the testers modified the carriage to allow the higher angle or it was produced through use of ground (firing off a reverse slope, from a ramp or digging a pit for the trail). None of this would be practical in the field and would surely contribute to damage.
I agree it is intriguing that these tests showed the French howitzer firing to that angle, but not the licorne. Perhaps it was a test to destruction, and the licornes fell apart before reaching that angle?
Paul has stated that the published range tables show a maximum elevation considerably less. It is probable that this maximum elevation is such that the piece can safely be fired at that elevation, so presumably there is a design envelope that would enable safe firing from a slightly greater angle.
How was such a piece to be aimed at such an angle, even if it did hold together?
I am quite intigued by this high angle test,