Seems that -
Bamber saw rabbits at around 9pm.
He went back out to shoot them. With several bullets. Minus sights and silencer.
Didn't fire a shot.
Left the rifle, magazine and bullets out. Although stayed inside WHF for several more minutes.
June didn't put anything away.
Nevill didn't put anything away.
Nevill didn't put anything away again at 3am.
No one has a suggestion of what Nevill was doing when Sheila loaded, chambered and breached the rifle. Except that he was in the kitchen with Sheila.