  In this paper we use recent X-ray and radio observations of the ejecta-rich
Galactic supernova remnant (SNR) G337.2-0.7 to determine properties of the
supernova (SN) explosion that formed this source. H I absorption measurements
from the Australia Telescope Compact Array (ATCA) constrain the distance to
G337.2-0.7 to lie between 2.0 +/- 0.5 and 9.3 +/- 0.3 kpc. Combined with a
clear radio image of the outer blast-wave, this distance allows us to estimate
the dynamical age (between 750 and 3500 years) from the global X-ray spectrum
obtained with the XMM-Newton and Chandra observatories. The presence of ejecta
is confirmed by the pattern of fitted relative abundances, which show Mg, Ar
and Fe to be less enriched (compared to solar) than Si, S or Ca, and the ratio
of Ca to Si to be 3.4 +/- 0.8 times the solar value (under the assumption of a
single electron temperature and single ionization timescale). With the addition
of a solar abundance component for emission from the blast-wave, these
abundances (with the exception of Fe) resemble the ejecta of a Type Ia, rather
than core-collapse, SN. Comparing directly to models of the ejecta and
blast-wave X-ray emission calculated by evolving realistic SN Ia explosions to
the remnant stage allows us to deduce that one-dimensional delayed detonation
and pulsed delayed detonation models can indeed reproduce the major features of
the global spectrum. In particular, stratification of the ejecta, with the Fe
shocked most recently, is required to explain the lack of prominent Fe-K
emission.
