Can we just leave this alone now? Nobody ever suggested lubing brass to be fired in any mil-surps except biged, and everyone here knows damn well a modern action is built far stronger than needed, so there is really nothing to discuss.
And I really don't give a $--T about what the British or the US Military have to say about anything, especially their thoughts on how to handload ammo, load my rifle, or shoot my rifle either.
I don't need any fancy equations or illustrations to demonstrate the strength of the action my rifle is built around. I have seen how thick the bolt and action lugs are as well as the action itself, and I have a good idea of the strength of the steel. I am very comfortable with it's strength and confident it would take an act of god or one hell of an overcharge or major screw-up of some type for the action to break/explode/shear a lug or have any other serious failure occur.
And just to prove a point, I did an experiment today with my Mosin "parts gun", which is just a mixed-up and mismatched mess of spare parts that I put together as a complete rifle. The rifle started out as a barreled action that I bought to scavenge the bolt and sights, and every other piece has been replaced with parts left over from upgrading other Mosin's. But the rifle has near perfect headspace, as the bolt will close with a .001" shim behind a go gauge, but not a .002 shim. Needless to say, I really don't care about the rifle a whole lot.
I loaded up 25 rounds to use for testing, 45grs of H4895, Hornady 174gr RN, CCI std. LR primers, loaded to mag length and then lubed over the entire case with Imperial Sizing Wax. 20 of the rounds were lubed lightly, and I went
HEAVY on the last 5 just to see what would happen ;D
So I went down to a local gravel pit, strapped the Mosin into my gas dampened rest that has a remote trigger pull system, aimed it at a large dirt mound, climbed inside a large concrete tube, (the kind that they use for drainage system junctions with a manhole cover on top, about 8" thick and re-bar reinforced) and proceeded to fire 20 rounds off into the dirt pile, swabbing the bore with brake cleaner and a dry patch between each shot to ensure it was free of lube. I never swabbed the chamber and left the lube to build up. About the only difference I noticed was the bolt was a bit hard to lift, other than that it was the same as dry rounds. (Mosin's are well known for having a "sticky" bolt that can be hard to open)
After the first 20 rounds I checked the headspace after swabbing the bore and chamber, still the same as before, closing on a .001" shim, and not closing on a .002" shim.
Now for the 5 rounds with enough Imperial slathered on them to FL size 100 cases.

I proceeded to fire these 5 rounds in the same fashion as before, swabbing the bore dry after every round and leaving the chamber alone. Now I need a rubber mallet to whack the bolt open, but it still opens and extracts the empty cases every time.
I re-checked the headspace one last time after swabbing out the chamber and bore, and again it's the same as it has always been, closes on the .001 shim, won't close on the .002.
I have dropped the bolt off at a local engine shop I used to work at to be magna-fluxed as well to check the lugs for cracking. This way I will know for sure if I have done any damage or not, and that way I can either prove or disprove the whole "dangerous case lube" theory.
So after abusing the poor Mosin, all I can tell is that the action of the Mosin Nagant is built VERY strong! With the big lugs on the bolt head and the third on the bolt handle that locks into the ejection port, I doubt you could hurt the thing without some serious, deliberate effort.
So can we please just leave this discussion alone? I proved to myself without a doubt that it will be very difficult to damage an action to the point that it fails enough to cause injury. I abused an old mil-surp action beyond what most would ever do in normal use, and it still shows no sign of failure.
I would not hesitate one bit to lube cases for fire-forming in a modern action after what I saw today. They are just too well built to be damaged without some serious effort being put into it's destruction.
I am not looking to argue about this, so don't bother with any criticism. I have proved to myself that lubing cases lightly while fire-forming will not hurt anything. No book or article can give me the experience I gained today first-hand.
HOWEVER, I DO NOT SUGGEST THAT ANYONE ATTEMPT TO RECREATE THE EXPERIMENT I PERFORMED. I TOOK MANY PRECAUTIONS TO ENSURE MY OWN SAFETY AS WELL AS THE SAFETY OF OTHERS. IF YOU DO DECIDE TO TRY THIS, YOU DO SO AT YOUR OWN RISK AND I TAKE NO RESPONSIBILITY FOR YOUR ACTIONS!
CONSIDER YOURSELF WARNED!