Thanks, Len. I was hoping someone who had fired the stuff would post. Do you have any historical references to the particulars of the 3" canister and changes during the war?

I'm well aware of the density differences and size differences. The point is that the references I find are often self-conflicting or vague. With weight and canister length I can tell whether or not a round was lead or iron filled.

What sort of pattern do you see with the 3" rifles versus a 6 pounder smoothbore for instance? What I've read suggests the rifle distribution would be lumpy and wild while the smoothbore would give a more even distribution. That should make a smoothbore more effective at inflicing multiple single hits to personnel. I would expect that a lumpy pattern would either tend to put several hits on the same person, or miss nearly completely. I also expect that the smaller canister balls of rifles would be less inclined to bounce and inflict secondary hits. Theory is nice, but I would very much like to hear what you have observed.

I've read several statements that before the war lead was abandoned for canister in most rounds because it deformed on firing. But at the same time I read of later war rounds using increasing numbers of lead balls...particularly in rifles where large iron balls were not practical and the lower density would have required a much longer round to deliver the same weight. So that would be a tradeoff of ammunition chest logistics, loading practicality, and firing effect.