As to our fun bullets above, I would say that the big boy would weigh about a pound and likely had his birth in the magazine of a Hotchkiss Revolving Cannon. Doesn't look quite right for the Maxim Pom-Pom.
The little tiny one is something else. For one thing, that is an awfully long bullet for that weight; I would think that it could have a good big hollow in the base. I am using Text Book of Small Arms -1909 as my basic reference in this matter, backed up by Barnes' 'Cartridge of the World, 6th Edition' and between them they have come up with nothing that fits the bill entirely on this one. Bullet diameter is fine for several types, but we don't have it exactly. We DO have the length at 1.22" which means that if it indeed is a .45 caliber, it should weigh about 500 grains rather than the 365 which we know it weighs. Using these references, there appears to be no rifle using a .45-caliber bullet of 365 grains which is 1.22 inches in length.
Quality control in the late BP period often was not very good by our standards and ammo collectors as well as gun people have to get used to some pretty awesome variations. I would think the weight would be regarded as more important than the length of the bullet, and there were very few cartridges which used a 365 in a true large-bore rifle... and none of them were British, which meant that likely they also had right-hand rifling, which this bullet exhibits. I would think it more likely that this one came out of an Austrian Werndl than out of a Bulgarian or Russian
Berdan.
But I'm only guessing as to that, having eliminated the others through their own specs, and so I could well be wrong. C'mON you guys! There has to be somebody here that knows more than I do! Now's your chance to prove it, not that it's all that hard!
What do YOU think?