|The official SKN Brens supplied by Ordnance were all converted to a set drawing, by List and Co in Dagenham who did them on contract. Bert List, the owner of the Co also co designed the L34 silenced Sterling gun with Patchett. But I digress.
That the odd Armourer would skeletonise one was a bit of a myth really as he'd have to OBTAIN one to start with and that wasn't that easy.......
However, at Base Workshops where trade testing took place and at Training centres and Apprentice schools such as Carlisle, then it was a different matter and then a small group would section/skeletonise a part such as, say, a bipod assembly or a butt slide to illustrate this that and the other and so on. Same as L1A1's, No8's No4's etc etc etc. So, by default, these wouldn't conform to the original set, standardised pattern.
While it'd be fairly 'easy' to skeletonised the body, the same cannot be said for the breech block, piston, piston extension and piston post plus some other parts (the barrel nut is another.....) which are REALLY tough material. The barrel nut is both tough AND diamond hard. So is the bipod sleeve now that I think about it........ I say 'easy' to machine the othjer parts but I mean 'easy' if you have a large milling table and equipment to hold down the akward shape of the parts. Easy for training schools etc where time, breakages, equipment the gun etc doesn't cost anything but not if you are a dealer trying to make a profit.
Yhe difference between the standard model and what we call the classroom model is that the standard model just shows what you need to see to learn the gun - as a soldier would in training. A classroom model, as done by apprentices is that this would be done to show EVERY last movement of the action, the action of springs, where they anchor, the loading points, the action of mysterious items, such as the extractor stay in the cam groove and how it affects the rocking primary extraction and the bufferering of the unlocking phase.
Maybe someone could put up a picture of the bog standard skeletoinised gun. Incidentally, I gave an opinion on a SKN gun and Gloucester (?) Police weren't interested in taking it on a a 'firearm' capable of this that and the other.... Usdually have a SKN serial numbver but that isn't always the case as some have a later SKN SA63A 1234 number
Added a bit later....... Just been told by a PM that the place to see picture, albeit a bit old, B&W and blurred of a List/Ordnance SKN Bren gun is in the old LMG Infantry Training booklet.