Sutcliffe allegedly pointed and accidentally fired the sawn-off shotgun in the chest of Williamson as the trio drank in his bedroom. He died soon after.
She has pleaded not guilty to manslaughter.
Judge Connell said he did not blame Clegg for Williamson's death, but said given he was just five weeks out of prison, he should never have taken the shotgun and its ammunition to the house.
The sawn-off shotgun will be destroyed. Photo / Supplied
"Someone is now dead because you were just reckless as to what happened to that gun in your possession."
He accepted Clegg's remorse was genuine.
"Your grief and remorse appears to be genuine and you accept that you directly contributed to the death of your friend. There's no question here of you being someone who is callous in terms of what happened.
"But you were reckless in taking that gun to that party in those circumstances and leaving it in a position where someone else could take it and then this tragedy unfolded from there. That's your blameworthiness for all of this."
However, Judge Connell noted that in their victim impact statement, Williamson's parents expressed "strong views that you are the person responsible for the fatal shooting of their son".
"And they say it on the basis that you brought the weapon there. If you'd not left it there they consider that their son will still be alive and their lives would not have changed to the extent they have as a result of their son's death.
Rhys Williamson was shot in the bedroom of his home on Seddon Rd, Hamilton, on May 30. Photo / File
Clegg's lawyer Ted Walsh said his client had pleaded guilty at the earliest opportunity and he accepted the level of harm caused by his actions was high.
"The remorse is genuine. It is deeply felt and for him has become very much a watershed moment."
Clegg also realised he needed to start making positive changes to his life, he said.
"He needs to look at change, he's getting far too old for this sort of carry on. He knows that and he knows that whilst he has had this fascination with arms, that the probation officer sees, that that is something that the outcomes here have dramatically changed for this man."
Given his criminal history, especially with firearms, and the fact he was on release conditions from prison, the judge said he had no choice but to jail him.
"I fully accept that you did not intend that it should be used the way that it was [but] your recklessness in this is just extraordinary."
Judge Connell sentenced Clegg to two years' jail and ordered the destruction of the weapon and its ammunition.
