Assertion: gun's barrel | /r/HasProperty | fixed to movable base
Facets:
Source sentences:
text: The reduction in the size of the barrel was due to improvements in both iron technology and gunpowder manufacture, while the development of trunnions—projections at the side of the cannon as an integral part of the cast—allowed the barrel to be fixed to a more movable base, and also made raising or lowering the barrel much easier.