David Jolley, 40, of no fixed abode, was one of a group of men wearing balaclavas who forced their way into the farmhouse in Adlington, near Chorley.
The occupant, a 50 year old man, was tied up and threatened with a shotgun and a machete whilst the offenders demanded money and firearms.
Seven firearms were taken from a gun cabinet along with some ammunition and cash.
The robbers then made off in the owner’s Land Rover Discovery which was later found abandoned on Thirlmere Road, Blackrod.
A shotgun was discharged during the raid in November last year, although fortunately no one was hurt.
Jolley has been sentenced to life imprisonment at Preston Crown Court after he pleaded guilty to robbery and possession of a shotgun at an earlier hearing. He was ordered to serve a minimum term of six and a half years before he will be eligible for parole.
Two men aged 55 and one man aged 41 were also arrested on suspicion of robbery and have been bailed pending further enquiries until 8 May.
A third man aged 20 was also arrested but was later released without charge.
The investigation remains on-going.
DI Jo Keay from South CID said: “I am pleased that Jolley has been sentenced for his part in what was a truly shocking and violent robbery.
“The victim in this case was subjected to a terrifying attack and it is fortunate that he was not seriously hurt. I hope the fact that Jolley now faces a significant period of time in jail goes some way towards helping the victim come to terms with his ordeal.
“Our investigation into this incident remains on-going and we will not stop until those responsible have been brought to account for their actions.”