  We present the analysis of new X-ray observations of two Galactic radio
supernova remnants (SNRs), G337.2-0.7 and G309.2-0.6. Both remnants exhibit
line-rich thermal spectra that require highly non-solar elemental abundance
ratios. In each case, Si and S are unequivocally overabundant compared to solar
based purely on the measured equivalent width of the K$\alpha$ line complex.
Detailed nonequilibrium ionization spectral analysis of these remnants, using a
single temperature, single ionization age model, confirm the overabundances,
yielding Si, S and Ar abundances many times their solar values: 3 to 5 times
solar for G337.2-0.7 and greater than 3 to 10 times solar for G309.2-0.6. We
also find that for both remnants, Ne and Mg are underabundant relative to Si,
and for G309.2-0.6, Ca and Fe as well are relatively underabundant. This is the
first detection of metal-rich, non-solar abundance material in these remnants,
identifying them as young ejecta-dominated SNRs. Further support for their
youth comes from the distances that we estimate from the fitted column
densities (less than 15 kpc for G337.2-0.7, and $4 \pm 2$ kpc for G309.2-0.6).
  From the implied sizes of the remnants at these distances we infer relatively
young ages (2000 to 4500 years for G337.2-0.7, and 700 to 4000 years for
G309.2-0.6). Finally we note that no compact object has yet been found within
G337.2-0.7, but an X-ray point source is evident within the radio shell of
G309.2-0.6, although its nature remains unknown.
