  The predictions of hadronic interaction models for cosmic-ray induced air
showers contain inherent uncertainties due to limitations of available
accelerator data and theoretical understanding in the required energy and
rapidity regime. Differences between models are typically evaluated in the
range appropriate for cosmic-ray air shower arrays ($10^{15}$-$10^{20}$ eV).
However, accurate modelling of charged cosmic-ray measurements with ground
based gamma-ray observatories is becoming more and more important. We assess
the model predictions on the gross behaviour of measurable air shower
parameters in the energy (0.1-100 TeV) and altitude ranges most appropriate for
detection by ground-based gamma-ray observatories. We go on to investigate the
particle distributions just after the first interaction point, to examine how
differences in the micro-physics of the models may compound into differences in
the gross air shower behaviour. Differences between the models above 1 TeV are
typically less than 10%. However, we find the largest variation in particle
densities at ground at the lowest energy tested (100 GeV), resulting from
striking differences in the early stages of shower development.
