Choosing a musket for a Revolutionary War militia impression.
One of the more costly (and thus difficult) choices to make when equipping for a Revolutionary war militia (or early war Continental soldier) impression is firearm choice. Like many modern conflicts, the early battles of the Revolutionary war were frequently fought with the leftovers from the last war; the French and Indian or Seven Years war. In choosing a plausible firelock for this impression, it is a good idea to nail down what actually existed and was common in the area being represented. Sadly, great lists like this one from Hyde County NC are rare items, but it does a great job of showing the diversity in arms that some militia companies fielded. Luckily, three main front runners have been identified for "common" muskets from the prior conflict that were imported for provincial use and were very widespread in the colonies. This list is in no way all inclusive, many other varieties can be documented in almost every colony (for instance, small amounts of captured Spanish muskets in Massachusetts and Pennsylvania, as well as local restocks and etc), but these three main options offer "safe" choices via documented usage in large numbers in the colonies below (the majority of them are found through primary documents but some via excavated parts, feel free to inquire about any specifics that are omitted here). If the impression doesn't require a bayonet, English import fowling pieces with walnut stocks and 4 foot barrels should be considered as they were likely the most common gun in British America during this period.
Muskets of the King's pattern:
Pattern 1742 muskets were the workhorses of the French and Indian War, half of all imported muskets from the Tower were of this type (well over 10,000 stands). In addition, some earlier guns (Pattern 1730s, Queen Anne era muskets) can be documented in some places. The best reproduction option that is currently available is from the Rifle Shoppe or parts from Track of the Wolf, although some have had success reworking Pedersoli short land muskets, however they will be 4 inches too short in the barrel. As an aside, before buying or building anything I recommend you do yourself a favor and compare any reproduction muskets with the illustrations in Goldstein and Mowbray's The Brown Bess; An Identification Guide and Illustrated Study of Britain's Most Famous Musket.
Dutch Muskets were the second most commonly imported guns from Ordnance stores during the F&I era for use here. The best reproduction option that is currently available is from the Rifle Shoppe (Dutch type II series 693 without barrel bands).
Wilson commercial military style muskets:
Wilson commercial military style muskets saw wide spread use in various configurations, generally following the lines of King's Pattern guns with lighter and cheaper furniture. The best reproduction option that is currently available for these is from the Rifle Shoppe (Series 671), although some have had success reworking Pedersoli short land muskets (furniture swap, remarking), they will be about 4 inches too short in the barrel for most of the earlier applications (A surviving NY Wilson musket has been shortened to 42 inches and there are surviving military style fusees that appear to have been that length from the start). Another kit that might work towards a Wilson or other commercial musket/fusil model after swapping some furniture some of those shorter non musket bore variations is the Chamber's Fusil Kit -in addition Caywood stocks a Wilson marked lock, although the bulk of the Wilson military guns were simply marked under the pan without the additional engraving.