Mike,
I'm planning on writing a series of threads on the rifle, the ballistics, the bullets, cartridge, magazine and moderator, and a more detailed critique of Malcolm Fletcher's witness statement, but for now, just some thoughts:
(i). To be clear, the malfunctions identified would not in and of themselves interfere with the barrel or the passage of a bullet from the crimping. You would not have a squib load with these problems, for instance.
(ii). The stuck cartridge casing in the ejector port is not that serious, and if it was a recurrent malfunction, was probably caused by dirt/poor upkeep, or mundane mishandling, etc., as Fletcher states (including mistakes that somebody like Sheila could make, such as misusing the bolt or improperly gripping the gun - as an example, look up 'limp-wristing' in the context of firearms), but it can also be caused by a poorly-received magazine. It's resolved by the obvious expedient of simply sweeping one's hand over the offending cartridge to remove it from the port. Failing that, you can tap the magazine in order to ensure that the cartridge is correctly chambering and seating. You could also (after tapping the magazine) try opening the bolt and seeing if the cartridge falls out, and if it does, you close the bolt to re-chamber; if the stuck cartridge doesn't eject, then you'd have to detach the magazine and re-attach it with a firm tap, correcting any obvious problems in the process like double-chambering. It would be very much trial-and-error.
(iii). I did open a thread speculating about the possibility that Jeremy-as-killer could have 're-clipped' when carrying out the massacre, as it does seem unlikely - on a time-and-motion basis and taking into account the presence of Nevill - that he (or indeed Sheila) could have done this otherwise. Here's the thread:
http://jeremybamberforum.co.uk/index.php/topic,9367.0.html It occurs to me that the rifle malfunctioning might be relevant to this problem. Apart from anything else, it's possible that the reason for the stuck cartridge problem could be that at least two magazines had been used in the rifle recently and maybe the magazine that Fletcher had with the gun was of a kind that didn't fit into the receiver quite as well as optimal.
(iv). The open breechblock is the more serious of the two problems, as the rimmed block holds the crimped cartridge in the breech and stops it falling back into the seat of the rifle. That would cause the rifle to, in effect, 'jam' every one or two shots. One way to resolve it temporarily would be to tap the end of the barrel on the floor with the 'safety' on (not officially recommended, but the sort of thing an ordinary gun user might do), however the problem would recur every one or two further shots until resolved properly.
(v). That in turn leads me on to speculate how Sheila, a naive gun user, might have resolved such a problem while carrying our the massacre. What to look for is signs of a gun barrel (or maybe even the stock) having been banged into something. Here I venture into the realm of pure speculation, but ballistical malfunctioning may account for the damaged rifle stock and at least some of the damage in the kitchen - whether it was an attempt to resolve a malfunction or just Sheila acting out her rage due to problems with the rifle. There's also the possibility that a rifle malfunction may explain the supposed "burn marks" on Nevill. Maybe Sheila banged the rifle on the AGA and then inadvertently pressed the hot barrel into Nevill or Nevill's corpse? (Contact with the AGA could also have been accidental, of course, especially if Sheila was inexperienced with guns).
(vi). I also wonder, could a recurrent rifle malfunction explain why the rifle was found unloaded? In other words: let us suppose that Sheila is having problems with the rifle, this will lead her to mess around with it and examine it, perhaps (out of instinct) bang it on the floor, and she might just put one or two more bullets in it, maybe one bullet at a time.
(vii). Of course, an important point is that if Jeremy did this and attacked Nevill with the rifle butt, that would also potentially result in malfunctioning.
