been
reached. A little brown carbon was found in the chamber, which was
easily destroyed by boiling sulphuric acid and nitre with no residue.
There was a small crystalline residue from the melted layer of the end
plug, from which was isolated one non-polarising crystal, probably
diamond, but too small to identify with absolute certainty.
Considering
the light weight of the piston and the short duration of the exposure
to heat, also the small diameter and volume of the end clearance space,
the observed effects would seem to indicate that a very abnormal
temperature had been reached, many times greater than exists in the
chambers of large guns. There was, however, no evidence of any melting
and recrystallisation of the free carbon present.
Experiments with high velocity bullets
As
it seemed desirable to try the effect of still higher pressures, a
rifle, 0-303 inch bore, was fitted with a specially strong breech
mechanism by Rigby, capable of withstanding a charge of cordite 90 per
cent, in excess of the service charge.
