There has to be a difference between what MV you can generate from a 7.5" barrel, and an 11" barrel. I don't know the numbers, as I have never chronographed a smoothbore .62 caliber pistol. You are burning almost 50% more powder in the longer barrel.
But, a large, soft, .62 cal. RB is going to deliver a lot More of its energy on any flesh and blood target, than most .44 magnums.
The howdahs were not used as the principle weapon to hunt tigers. Instead, they were purely defensive guns, to protect the hunters, and his elephant from a Tiger that attacked him, trying to escape the beaters who were driving the tiger to the hunters.
We see DBL S x S Howdah replicas made today, but not the 4 barrel variety. Single barrel ML shotguns, cut down, and some old single shot ML rifles continue to show up on foreign markets, but cannot be imported, usually, into the USA.
So far, ATFE has not declared these modern "replicas" to be Class 3 firearms, requiring registration, tax stamp, etc. That will all end the first time one of these replicas is used to kill someone in an armed robbery/murder, I suspect.
As to the Taylor "Knock Down" formula, it was designed to compare bullets, not RBs. People seem to want to misuse it all the time. Since all these formulas only give a relative "Index" to a particular caliber, and bullet, it does little harm to talk about it. The real test comes in the field, where, as has been pointed out, there are so many variables that affect how a particular projectile acts on a live animal( or man), that all these "formulas" meet the same fate as war plans after the first shot is fired. Somehow, Tigers have a way of reminding people that they can't READ those formulas. :shocked2: :haha: :hmm: :surrender: