@scipio.
In different posts over the past few days I got the impression that you believe the telescopic sight was already attached during the assault, then removed afterwards, perhaps because of the following in blue from the 2002 Court of Appeal Document...
13. The rifle was a .22 Anschutz automatic rifle. Together with a Parker Hale sound moderator (silencer) and telescopic sights, it had been bought by Nevill Bamber on 30 November 1984. 500 rounds of ammunition had also been purchased. There was evidence that the gun was used to shoot rabbits and would only ever be used with the sound moderator and the telescopic sights attached. A screwdriver was required to remove the telescopic sights but there was evidence that this was not normally done because of the time it took to realign them.
and...
20. cont... Relevant events before 7 August 1985 21. Anthony Pargeter, Nevill Bamber's nephew and a competition standard shot, stayed at White House Farm between 26-28 July 1985. He saw the .22 rifle in the gun cupboard in the ground floor office. The telescopic sights and sound moderator were attached and the gun appeared in a "new" condition. There were no scratches or marks upon it. Later the appellant, himself a good shot, took the rifle out for some target practice.
and...
35. Upstairs the bodies of June Bamber and Sheila Caffell were found on the floor of the main bedroom. That of Mrs Bamber was very heavily bloodstained and lay by the doorway. Sheila Caffell's body was by her parents bed. The .22 rifle (with the sound moderator and telescopic sights removed) was on her body with her right hand resting lightly upon it and with the muzzle of the weapon just below wounds to her neck. Immediately to her right, resting on the upper right arm and the floor, was a Bible that belonged to June Bamber.
This is probably why you said the sight caused some of the damage to Nevill's face and arms, and could also have injured Jeremy Bamber's hands.
But according to Roger Wilkes (Blood Relations) who interviewed members of the family...
At Bourtree Cottage on the morning after the murders when questioned by David Boutflour, Jeremy Bamber said he had taken the telescopic sight (and silencer) off before he went out to rabbit hunting the previous night, so that it would fit in the gun cupboard afterwards. This struck David as strange, because even with the sight fixed but without silencer, there was enough room for the rifle to fit. So why did he take the sight off at all, when it had been fully functional beforehand, especially if he was soon about to shoot rabbits from a distance!
The only true reason for its removal as far as I can see was to make it easier to handle without obstruction at close quarters in a planned assault within the confines of White House Farm.
From my own experience with a Nikko-Stirling that I once removed from an air-rifle, I found out how time-consuming and involved it was to zero-in again to anything like the accuracy it was before.
Lesson learned: If it works fine, don't fix it.
I am not convinced that the scope had been removed at the time of the murders. I am not even convinced that Jeremy actually took out the gun, loaded it, unloaded it and left it to be accessed later. These claims come from Jeremy alone. He has eveyr reaosn to lie and has been caught in numerous lies so I don't particularly believe him. It is quite possible that he slipped in the house when everyone was asleep, fetched the gun, loaded it at that point including the magazine and that he left the scope and silencer both attached as they were when he found the weapon. I am not going to rule out the scope being attached just on his say so. Thus it will always be possible to me that the scope had a role we are unaware of and that to this day was not looked at.
The testimony tends to establish the gun always had the scope and silencer attached. Jeremy though claims they were not usually attached and had not been attached when he retrieved it. There were other guns in the same closet though that had scopes and even a silencer attached. Jeremy's claim he sought out a gun with no scope to go shhot bunnies makes no sense. I would use open sights for a large target maybe but not a bunny. I would want to use a scope and I would even want a scope for a larger animal. I first learned to shoot with open sights. We didn't get to use scopes until later on in our training and in the field. Scopes are considerably better than open sights. It was relatively late out so why would he want to skip the suppressor as well and disturb neighbors even if the neighbors were not overly close? In fact the main reaosn for the supporessor is not even to reduce recoil it is so that the noise doesn't hurt your ears. A suppressor is not silent as they show on television, not most of them anyway because there are other factors at play. But a suppressor like this reduces the noise enough so that it doesn't hurt your ears so you don't need to use earplugs. So it makes no sense to choose the weapon he claimed he did. But worse he didn't just find the gun lacking the suppressor and scope as he claims. If the gun was indeed left by him on the kitchen table without these accessories it means he removed them. Removing them makes no sense though for going to shoot bunnies there had to be a different motive as you suggest.
We know for a fact the suppressor was used in the murders. The defense even conceded this point at trial the defense maintained it was Nevill and June's blood in the supporessor and that Sheila removed it before killing herself.
Here is the entire field of possibilities related to the suppressor:
1) it was a lie Jeremy left the gun out at all and in fact the gun was in the closet with the suppressor and scope attached and Jeremy used it in such fashion then removed both accessories after the murders and put them away
2) it was a lie Jeremy left the gun out at all and in fact the gun was in the closet with the suppressor and scope attached but Jeremy removed the scope before committing the murders
3) Jeremy removed the scope but not the suppressor and left it on the table
4) Jeremy left the gun on the table as he claims and the killer later fetched the suppressor and installed it before committing the murders
The defense maintains number 4 is what happened. Number 4 is not consistent with someone being in a crazy rage simply grabbing the gun though form the table. It demonstrates rational thinking. So if that is what happened it doesn't fit with how Sheila was supposed to be acting.
Even if Jeremy had left the gun on the table I don't think Nevill and June would have left the gun and bullets and set the table around them. Jeremy would have to expect his parents to put the gun somewhere else and tha the would have to go search for it. He had no need to leave it on the table. If he did prep the gun in advance he could leave it and the bullets hidden in a place where he could find it but no one else was likely to tamper with or even just in the closet and retrive it when he was ready to commit the murders.
The tale of leaving it on the kitchen table was a contrived one. He invented that tale so people would believe Sheila was having a psychotic episode, the gun and bullets were right there in front of her face and all she had to do was slap a magazine in not load the clip so Nevill could not disarm her safely. He was scared to try to disarm her and instead called Jeremy to do it. I don't believe tha the took out the gun and left it on the table with the bullets. I believe Jeremy made up this tale to get police to believe that Sheila did it. The same way he made up the claim she had fired all guns in the house and was proficient with them to get police to believe she did it. He said the suppressor was not attached at this point though it was. Why did he says it wasn't attached? Well first of all he didn't want anyone to know it was used during the crimes. But also with the suppressor attached the gun would be hanging off the table. The gun would be too long to fit anywhere natural in the room. That is even more reason why it would have been put away by Nevill or June aside from just the twins being tempted by it.
His claim the suppressor was not on the gun was worthless and clearly a lie. I don't believe he removed it then put it back on later. He lied about the suppressor so why not the scope? I therefore am not conviced that the scope was not attached at the time of the murders. He could have removed it but he might not have. I won't write it off just on his say so. Because no one thought about this possibility no one looked for marks to match to it. They didn't inspect Jeremy at all which was a giant loss of potential evidence.