The standard Anschutz is about 43" long. If you've got a Stanley tape measure, extend and lock it at 43", plus another 7" if you think a moderator was fitted, hold it to your shoulder over a double bed at the foot end and see how close the rifle muzzle might have been to the head of someone in the act of getting up.
http://jga.anschuetz-sport.com/index.php5?produktID=313&menu=106&seite=51&sprache=1&produktShow=detail&dlfotos=1&PHPSESSID=77f29b217478cf5d82b7c0201cc4e627
You forgot about the other two wounds to Nevill's left shoulder and arm. Where did the ejected casings finish up if SC then had to move out of the doorway onto the landing to get those shots in as Nevill stumbled downstairs back to the kitchen? They couldn't have been DRH 13 and 14, because the casings ejected up and forward to the right and must have flown over the banister rail onto the lower staircase treads.
In any event, Jeremy Bamber's whole phone call story is unbelievable. It's impossible to think that Nevill would allow his daughter to slip past him in the kitchen armed with a loaded rifle while he fumbled about dialling a six-figure number, then waited for his son to wake from a deep sleep (in his own words "like a log") before answering. Any father's first move would be to follow his daughter immediately and disarm her before she had the chance to fire off any shots.
https://soundcloud.com/user9618130/jeremy-bamber-fathers-alleged-phone-call
If Sheila had "the gun" (as quoted by Bamber), which presumably meant holding it, being in charge of it, and knowing how to chamber and reload it, there could not have been an opportunity for Ralph to step away from the situation and waste precious time calling Bamber, and hoping that he'd eventually pick up. If at this stage no one had been injured, Ralph would have done his utmost to reason with her, calm her down, disarm her. If Ralph had already been injured, there WOULD have been blood on and around the phone (the first point that I made on blue, years ago). If June and the twins had obviously been shot and probably mortally wounded yet Ralph hadn't, he would have done his best to escape from the farm and run to the nearest cottage for help. If he THEN called Bamber, it would have been to warn him, not invite him into danger. These are simple facts that Bamber failed to think through.
Plus.....the blood spots on the bedroom carpet were never properly analysed (as Scipio has pointed out) so some of them could have been from Ralph.
Seriously, what are the chances that the whole family were at the farm, the phones were dodgy and all over the place, Bamber had a new gun that had nothing to do with farming, he'd been bragging about being Lord of the manor, he'd told Julie about his plans (if you believe her or not, personally I do because she had so much to lose she could have been ripped to bits in court if she was lying) and why did Bamber ask Sheila when she and the boys would next be visiting the farm? He had never shown the slightest interest before. And his behaviour during and after the loss of the only family he'd ever known was shameful.
And...the caravan park robbery.