Brian Ferrill, 62, who runs a chain of restaurants, claimed the Smith and Wesson gun went off accidentally after he returned from a Remembrance Day parade.
His wife Maureen, also 62, was killed instantly by a single bullet at their country home in the village of St Athan, South Glamorgan.
At Cardiff Crown Court yesterday, Ferrill admitted manslaughter and was sentenced to 12 months' imprisonment, suspended for two years.
The court had been told how Ferrill, a former flight- lieutenant and drill instructor, was practising speed loading when the gun went off.
John Charles Rees QC, for the defence, said: 'He pointed the gun in the opposite direction to where his wife was sitting and pressed the chamber release button to empty the cartridge.
'But it did not work. He thought it was jammed and without thinking he turned the gun around and knocked the chamber to release it. He had done this several times in the past but as he knocked the chamber the gun accidentally went off and unfortunately shot his wife.
'He accepts that at some stage he must have, in error, cocked the gun.'Reuse content