Very good question indeed! I suppose the answer is: "it depends"..... I have a pre WWII 7x57R x 16 gauge 2 1/2" that I will forever be an unabashed troglodyte when selecting loads for it. I use Sierra game kings and Nosler ballistic tips in it and would sooner cut off an appendage before feeding it the mono metal Barnes TSX that I have come to love...... In my post-2000 vintage doubles, I wouldn't hesitate for a second to use the mono metals so long as they are of the driving band design.

I suppose each and every rifle would need to be metallurgically assessed for barrel steel strength, hidden flaws in the metal, build quality, soldering technique and so forth..... I would hazard a guess that the older combi guns don't tend to see so much field use from the general populace, and when they do let go, oh well, it was an old gun after all..... Maybe many are in possession of troglodyte personnel that have never managed a step past the good ole run of the mill Winchester PP or Remngton soft point old school standard ammo types.

I have personally managed to thoroughly bugger an exceptionally beautiful big bore Weatherby many many years ago using the early Barnes X bullets before driving bands were rediscovered..... The lustrous deep blue on the barrel clearly showed the imprint of the barrel rifling in a lovely and perfect spiral on the OUTSIDE of the barrel when held up to the light at the correct reflective angle. I have no doubt that such a bullet that could cause the permanent displacement of barrel steel in such a fashion would break solder joints with aplomb.

I suppose at the end of the day, it is your bar of soap and your shower and you can wash things as quickly or as slowly as you wish as the saying goes.......

. I personally would err on the side of caution. If the rifle was of little monetary or sentimental value, then I might be tempted, but...... my one and only combi gun is a lovely little Kersten lock, heavily and deeply engraved and gold inlaid, and I REALLY like it beyond its significant monetary value. In it, I will stick with those old traditional "soft" guilded jacket lead core soft point bullets and I drive them at moderate velocities as they were designed for...... I won't even use Nosler partitions in it for fear the stiffness of the partition might cause unwanted and unintended damage to the rifle barrel or solder joints..... If I want to chase power, velocity, and/or hunt heavier game, I will choose a different rifle. I am a fairly advanced hand loader and I would NEVER try to make this rifle something that it isn't.... I am old and slow enough to accept it within certain "period correct" conservative design parameters....... Maybe that is the answer.... What ammo was generally available when the gun was made? (Excepting Frankenstein creations like the non-driving band monolithic inventions that history has rejected in its infinite wisdom)