Diagnostic checking during a weapon transition is wasted time. Some people call it a chamber check but that can be confused verification of weapon status.
Diagnostic check: (verb) the act of reflexively canting a weapon that does not fire to the left and inspecting the bolt or slide position to diagnose the stoppage.
Diagnostic check: (verb) the act of reflexively canting a weapon that does not fire to the left and inspecting the bolt or slide position to diagnose the stoppage.