Omnivorous Bob:

I agree with your theory exactly. I've kept my hand close to my chest maybe for too long, in the hope that somebody out there had run a number of experimental tests that could be uncovered and reviewed. I guess there aren't any? I apologize for trying to drag it out, and if I've been annoying, well, sorry for that, too.

First; I want to emphasize tho the SHANK diameter as you mention. It should be no trick to design a mono bullet to be totally safe in thin-tubed guns AS LONG AS the dimensions of those guns' bores are known and their measurements worked around. Take about ten minutes including the time it takes to find the pencil.

Meaning, a "safe" mono bullet is a bullet that has an undersized shank and bands that allow the displacement of the metal impacted by the lands. BUT.......that bullet must fit the GUN.

As you say, I'll add. I can dent a piece of sheel steel with a brass hammer. I can SHATTER a hardened {but not tempered} knife blade with a piece of wood. Soft/hard only are relevant under the parameters you outline.

I do not think it is fair to categorically blame Barnes for their bullets in this sense. If the dimensions of their bullets are compatible with the internal dimension of the barrel shooting them, they'd be safe.

Now, I am going to tread lightly but say this as gently as I can. Whose responsibility is it to determine whether those dimensions are compatible?

Answer; The shooter.

Various causes can, I'm certain, be found for double damage. SOME THEM THE SHOOTER CANNOT REASONABLY BE EXPECTED TO PREVENT AND SOME OF THEM HE CAN.

I can wreck my gun with a normal powder charge and a soft cast lead bullet. How? By casting it so neck relief is inadequate to allow bullet release. An improperly fitting bullet will wreck any gun.

A bullet company makes bullets. The dimensions are known when a person lifts one from the box. They can easily be measured and so can the internal dimensions of the barrels. EVERYONE who owns a double should know every dimension of that double. Groove depth and land depth, neck relief and headspace, and acceptable OAL and max case length. Especially old ones. Just like most of us casters check our guns rigorously before shooting new bullets in them. IMO, every double before being shot should, in concert with its ammo, be rigourously miked, measured and checked, especially as and since as Peter noted earlier, Euro and American standards vary, and some guns might be out of spec in some way anyway. Screwing around with old clunkers has taught me to never trust the caliber stamp on the side of the barrel...NEVER. I mike, measure and doublecheck before I shoot.

This is why I find the statement by Barnes saying their bullets are better than the competition for the oldies to be, well, both possibly true and...amazingly crazy! They just might be fine IF the dimensions are compatible. If not...

I believe certain old guns are wrecked by merely firing them. Soldered barrels under stress from slightly improper fitting in the first place may not be noticeable, but may, afer years of sitting still or being used and EXACTLY LIKE AN OLD SOLDERED WATERPIPE, fail "for no reason" when a load is applied to them. Pardon me for saying, but fine doubles bear some similarity to your toilet supply line. {c'mon, guys, I'm trying to lighten the atmosphere here...

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The point is, solder fittings if done right are amazingly strong, but can give way under also-amazingly light stresses. Gunmakers I've discussed this with agree. The fitting is a tremendously skill-demanding process. I'm thinking that most of the non-double-owners out there have had an old, soldered sight base or two fall off, again, "for no reason". Similar condition.

It is possible that barrel harmonics and different bullet types could aggravate a conditon that lurks within the gun as well. This is the part of the mono equation that might be the hardest to duplicate in a lab, in my opinion. This one is kind of like a root ball somewhere in the dike. It's there by getting rid of it means finding it first, and we don't want to rip the whole dike down to find it...

I think we are going to see some experiments that will demonstrate the truth or falsehood of some of these theories. And they are, in my case, as in Bob's, theories. At any rate, they might give the shooting world a crutch to lean on when the greenies finally put the kibosh on lead bullets. {That copper may be far more toxic in the ground than lead is, well, a saga for another fireside...}