There are lots of things that aggravate me about re-enactors. Beards, too much stuff, too nice of food, etc. But the one that generally gets me the most is choice of gun.
For the most part, unless you are a Continental, you shouldn't carry a "Charleville", and if you aren't a British regular, you shouldn't carry a Short Land (2nd Model Bess). As an irregular (Tory/Rebel milita, Indian Dept., etc) we should be carrying fowlers, trade guns, composite guns, older muskets.The Short Lands and the "Charlevilles" used to be the only affordable options. Now it isn't the case.
For me, a trade gun would be a good option since I work along the Iroquois. These firelocks were imported by the hundreds by Sir William Johnson in the 1750-1774 time frame. They could be Type Gs, or O'Connor gun styles, etc. Light and fairly cheap, they would be an excellent choice.
The only mentions I have found of what anyone of Brant's Volunteers carried are a rifle that Joseph received as agift and Robert Land who was captured carrying a "musket with bayonet affixed."
A rifle is a possibility since my persona is a bit better off than most, but still fairly rare in 1770s NY. A trade gun sold for about 16 shillings, rifles at around 80 shillings. The Indian Dept. imported quite few Indian trade rifles, but where would a displaced Loyalist come up with that kind of cash? It's possible I could have owned before the "Troubles" and brought it with me.
Anyone showing up with something like a CVA "Kentucky" is strictly rediculous. Every unit shouls have at least one loaner gun (more on that later).
Another option for most of us is a composite musket. Built after a british pattern in the colonies by local gunmakers, these used whatever was handy. A British barrel, Dutch lock, homemade triggerguard, etc could all be found on the same piece. Many of these type turn up in collections, yet we rarely see one on the re-enactment field.
One such is the "Veeder Gun" in the collection of the Herkimer Home SHS in Little Falls, NY:
This is a British LLP (1756) re-stocked by a local gunsmith in what looks like curly maple. Carried by Tryon County (Rebel) Militiaman William Veeder from about 1778-1781, this is a prime example of what militiamen's guns looked like.
EVERY unit should have at least one loaner gun. Your 2 biggest initial expenses are usually your firelock and a tent. The guy new to the hobby isn't going to want to put out $600-1000 right off the bat before he knows whether or not this hobby (or your unit) are for him. Loaners are serious recruiting tools.