There were a lot of guys using X- military rifles - after all, those could be bought from forts for as little as $1.00
to $1.50 after they were declared obsolete.
That might have taken some time to acquire, but I doubt anyone went WEST without at least a Musket for protection.
In those, I'd expect the normal load would be a military issue load, also procured at the forts. Those would be single ball,
buck and ball and buckshot. Now, all of those for the .69 Muskets were of 165gr. musket powder, up until about 1820.
After that, the powder was improved and contained 135gr., still meant for prime and charge. The first cap-lock musket was 1842
in the US.
I guess the pilgrims be on their own for swan shot or other sizes, if small shot was even used. In some locals it was - #4 was used
in St. Louis by "Old Tom" with his 12 bore SxS with 48" barrels. Tom was a market hunter and had a contest against a visiting English
Sportsman who had a 26" barreled 14 bore Sxs, which Tom called a "Little Pistol". They used #4's and shot at a target at 75 yards
distance. The person shooting who put the highest # of pellets on the 4" X 7" piece of paper was the winner of the other guy's gun.
The little pistol won, as he used an Ely 1oz. wire basket concentrator designed for killing ducks at 80- 90yards. His little 14 bore put 28 pellets on his 4x7" paper.
Old Tom's gun made 7 hits, iirc. Both guns were non-choked.
As to RB's I assume the non-musket shooting handloader used wads with balls, not patches, same as was carried over into the 20th century, with punkin-ball loads.
In those, grossly undersized round balls were loaded between wads. The ball careened down the bores and shot very randomly.