If memory serves my right The Hudson Bay Company used to carry 1/2 pounders (2 gauge) in musket configuration for taking out a competitor's canoe.  I have seen one fired without the bullet at Old Fort William, in Thunder Bay Ont.  Has anyone fired a live round out that class of flintlock?
  That thing would give you reason to reach for the lineament.

(If I am wrong about the caliber let me know.  Its been 6 years since I have been there)

-MD

I did some research online tonight.  I would say that the gun was a 4 Gage.    That is about a 1 inch round ball.

-MD

There used to be shotguns they mounted in the bow of the boats. And they would then get in range of waterfowl sitting on the water. When the birds took flight, they would flock shoot them. And I once got to see a 4 gauge shot. But I never shot one. And glad I did not have to. It was something to see.

Those muzzleloaders they used to flock shoot were known as punt guns. There were many versions some having numerous smaller barrels each pointed slightly off the one next to it and then there were the huge single barreled guns. Some were really big looking like a piece of rain pipe for a barrel. These were mounted to a small boat called a punt. The poacher would lay down in the punt and slowly approach a large flock of ducks or geese and when in range would touch off the gun. The recoil would litterally back up the boat maybe 10 feet or so. These guns were very oversized muzzleloading shot guns and used huge amounts of powder and shot. Many years ago I actually met one of those poachers who as a young man had done it. I have seen a couple of those punt guns in person on display on Assatague Island VA.

I have shot a 4 bore  punt gun with some lite loads and it still kicked like a mule but was fun  a round ball out of them shure puts a big hole in some thing  have also shot a old wall gun of 1 1/2 bore  they have a orelock on the stock to put in the wall it helps with the recoil of the gun both were flintlocks.

I mentioned to one of the re-en actors that they should put bird shot in it and take out the geese eating the grass. The fort is depicting the early 1800's. I just thought it was interesting that instead of using cannons they would use that large bore flintlock.

-MD

It's called light artillery small crew served weapon 

The size of some of those punt guns could put them in the cannon status. Something like a cannon with a stock. Powder and shot were measured by the handfull. If memory serves which at my age it usually doesen't some of those punt guns use up to a half pound of powder.

many of the expiditions carried the market guns for both substanance hunting and for protection..loaded with buck and ball it would/could wipe out a bunch of your foe in one shot...and scare the crap out of the rest of them....

"Buck an ball" used to be a standard hunting load for smooth bores.
Don't know if it was a flinter or not but one old time elephant hunter used a 2 bore rifle he called "baby", he said it spun him around and made his nose bleed every time he shot it. Far too brutal for me.

Don't want to brag but I aint had no complaints from the ladies.

Yeahbut . your flint is on end of a spear you chopped down in woods....