I make them to earn most of my living and I have used them since the very early 70s to hunt too.

I shoot a 62 for the most part. I have killed a moose and a buffalo as well as several elk and deer and a few antelope with it.
The larger bore sizes for the flintlock era of arms simply shoot more lead and more powder. The moose I killed fell at the shot and the ball broke the shoulders and exited. A 62 cal ball (.600 actually ) weighs around 320 grains. I cast them from Wheel Weights so they don't flatten much and they go through everything I shoot as a rule.

So bore size with early slow rifling added ball weight. Bullets don't stabilize well in long slow twits barrels. I have made a few English style flinters rifled for bullets and they work very well, but the flash hole liners must be changed out about every 300 shots because the added pressure from a 400-450 grain bullet erodes the vents a lot faster. (I have one for sale right now in fact)

A big bore like a 62 looks huge, but remember balls are the lightest projectiles to fit in any given bore size. So a 66 cal (16 bore) is a 1 OZ gun. 437 grains is a lot of lead, but not much larger then most 45-70 bullets and less then some of the early 500 grain loads.

I also shoot a 50 and I have killed a lot of game with 50s, but they don't do the damage a 62 will do, or a 54, or a 58. Simple physics. The down side, just like with modern guns is recoil. A 62 kicks harder then a 58 or 54 or 50. You can make it kick no more than a 50 by using less powder, but that means less velocity and the larger slower ball is not really any more effect at that point. But if we have a MV of (let say) 1750 FPS for all guns obviously the heavier ball and larger charge of power is going to kick more. But with a 140 grain charge of 3F and a 320 grain ball my 62 cal flinter kicks no more then a 300 mag. Not "nothing" but not all that hard. A 58 is less, say 30-06. A 54 feels like a 300 savage and a 50 is around the same as a 30-30 in it's kick

Here is a pic of my 62. It's filled a lot of freezer space for me over the past few decades.
[Linked Image from live.staticflickr.com]My Rifle 3 by Steve Zihn, on [bleep]

Last edited by szihn; 01/29/23.