I am not going to contine to do this as I am finding it boreing, and I'm going to Africa in the morning.

You were not simply making a comment on third fastners, many of which do not touch in normal use and are a safety of last resort. The reason that they do not touch is that if they were that perfectly fitted you would not close the action, they require a clearence fit. It might be possible with a tapered pin cross bolt, alla Greener style (which is not normally tapered. However wear would soon reduce that to clearence unless the pin protruded at the start of its life to allow for wear (they do not) Dols heads cannot influence the tightness of the action unless the barrels move off the face in a straight line before they start to pivot, as the design allows free rotation around the hinge pin or again you could not open the action. One could conjecture that if an action is off the face then they will contribute, but then again if it is that far off face it needs rejointing anyway.
You are fully entitled to your opinion, this is a free forum and you may express, as the people that run it say, anything providing you do so politely.
I respect your right to hold any opinion about any rifle or anything else.
If you had written only the last two sentences of your opening post and left it at that then fine.

But you dident.

You make sweeping statments that are not borne out by the physics or general engineering principles.
This is the area for gunsmithing and building double rifles. People come here looking for knowledge and it ill behoves anybody to submit misleading information as factual statment.
And you have just done it again:

Quote "Regarding the over/under, The fact that the lower barrel is essentially surounded in the action bar makes it far stronger than the sxs action and yes the top barrel may impart higher bending moments and so those in the know opt for, In the interest of safety ,a 3rd or 4 fasteners.. correct!" End quote

What do you mean by "those in the know" Beretta make a huge number of very fine O/U's They hinge on stub pins of substancially smaller bearing surface than any s/s underlugs and are bolted without a single underlug, but two pins protruding from the action face. Ultimatly if subjected to enough stress the two sides of the action would flex and the breech be unsuported. They are however more than strong enough for their designed intention. That is the basis of engineering calculation.

As to the Weatherby's To quote Lyman 48th edition Page 284 " 416 Weatherby Magnum ..The slowest powders are ideal..For full power loads IMR 7828 is the wisest selection""

Allient recomend RL22 (website)
Hodgdon nothing faster than 4350 except for the single H414 loading for the light for calibre 300 grain Barnes.
For .470 NE Hodgdon do not go faster than H4350.

QUOTE "The Wheatherby line of cartridges are loaded to the max case cpacity and operate at upwards of 62,000 psi. the free bore allows to bullet to move unimpeded by the friction of the rifling
thus keeping the pressure curve more gradual." END

Do you see the contridiction. You are acknowledging after I raised it, what Weatherby's know due to their development work, they require a slower Pt curve. Two posts above you are advocating powders that

Quote "The faster the rise and fall in pressure the better. " End

You are advising RL 15 and faster, for applications not recommended by the manufacturers themselves.
If you want to do it, it is a free world and many of us do it or similar things based on our own risk/benifit assesments. I have a 6mm BR Ruger #1 running loads I wouldent publish anywhere, give to anybody else to shoot and certainly not advocate.

It bothers me not the slightest what you think of me, but when you write, Quote "Citing these principals looks good on paper to some people but it's mostly elementary." You are wrong. Lots of people come here with little knowledge seeking enlightenment. You are putting them at risk.

You were incorrect about the pressure required to obdurate a chamber with a brass case, perhaps you are better informed now, although you are not likley to admit it in print. Stick around here a while and there is loads of interesting information and stories and some great people, some of whom I have been privilidged to meet.

IMHO ( see polite) What you are doing is silly.

I wish you well for your trip to Cameroun.

Best wishes