Misrun

The reasons for cold shut or misrun may be too thin sections, improper gating system, slow and intermittent pouring, poor fluidity of metal.

Source: wiktionary

When wall thickness is decreased to less than 1/16 in., adequate mold filling becomes almost impossible, except for extremely short distances, and misruns result because of the freezing of metal before the mold is filled.

Source: wiktionary

A misrun is caused when the metal is unable to fill the mould cavity completely and thus leaves unfilled cavities.

Source: wiktionary

If the molten metal is too cold or casting is too thin, entire mould may not be filled during pouring before the metal starts solidifying and result in misrun.

Source: wiktionary