I thought the silencer was designed espescially for shooting vermin. Such as rabbits.
If Bamber saw rabbits and surprisingly decided the situation was worthy of going to try to negate them, surely it was worth putting a silencer on.
Maybe Bamber didn't believe he had time to put it on. However he had time to fully load the rifle.
Bamber said he saw rabbits, rather than one rabbit. Being a farmer and proficient with the rifle he would know that after one shot without the silencer on, all the rabbits would dispearse. So why bother fully loading the rifle ?
If the rabbits were so dangerous, surely it was worth shooting or attempting to shoot them all.
Or maybe the silencer was already on the rifle. A relative said he saw the rifle with the silencer attached shortly before the massacre. There really was no reason to take it off as it still fitted in the gun cupboard.
As it happened, Bamber went outside and didn't fire a single shot at the rabbits. They must have all dispersed in a short period.