Marrakai,

Yes, chambering the wrong round is always a possibility – but there are already plenty of other opportunities for this. The majority of Black Powder Express cartridges had full Nitro equivalents. And yes, you do come across an old “blackie”, with bulged chambers where some fool had done exactly what you are concerned about. Curiously, the actions are rarely “sprung”, which leads me on to your last point about action strength…

I concede that the Greener Empire action is very strong, but there are some that would argue that long action bars(3 inches on non-ejector Empires – shorter on higher grade ejector models), allows for higher bending moment forces to be developed. The wider action bar will add to strength, but only marginally so; action depth, steel quality and precision of fitting are probably the major factors at play here. Most would agree, that so-called “3rd Fasteners” are merely cosmetic, with the possible exception of the Rigby and Bissel rising bolt system.

I think a more important safety issue is barrel and chamber wall thickness – all other things equal, a 10 bore action will allow for more barrel strength at the “business end”, because of the inherently larger standing breech. On another thread “Double Rifle Maker I’ve Not Heard Of..”, it is reported that 10 bore actions are being used for high intensity 14.5 x 114 MM SOVIET cartridges. I imagine, for this reason, but the seemingly ephemeral nature of the maker might cause one discount his use 10 bore actions as an endorsement! It must have held together for one shot surely!

Using a larger frame size, would allow you to use .600 NE head sizes cases, such as the 577 Rewa (Bertram has them too!); I think the chances of some “fool” happening along with one of those rare original rounds would be very slim indeed!

On your second point about jacketed pills developing less pressure than lead, yes – “fair dinkum” (and “ridgey – didge” too!). I remember reading this years ago, “somewhere”! The theory behind the observation was that soft lead, because of its ductility “upsets” more easily and maintains higher radial forces against the barrel wall right through it’s progress down the barrel. With jacketed projectiles, once the rifling has engraved on to it, in that part where the barrel is strongest, just down from the chamber, there is little resistance to it’s movement further down the barrel. The reason, presumably why there is generally more “taper” in the wall thickness of “Nitro” rifles than “Blackies”.

Yes, heavy walled Steel solids may be a different story, as Graeme Wright found in his tests, but it is SOP to load them back a bit!

Unfortunately, I can’t remember the original reference, but I did read a mention of this concept recently, thus it was on my mind when I posted. Now, all I’ve got to do is remember where I read that!

Perhaps, someone out there can come to my assistance on this?????????