Source: The First American Army by Bruce Chadwick.
pg.16 : "The much vaunted Pennsylvania rifleman, as bored as everyone else as the occupation and siege dragged on (Boston, Aug. 1775), spent many nights taking potshots at British soldiers in the city, or anyone they believed to be a British soldier, or, sometimes, anything that moved. Their marksmen did kill some soldiers and wounded others, but their aim was nowhere near as accurate as legend had it - and they all bragged -and they often shot up the homes of residents. One night a rifleman mistook another rifleman for a British soldier and shot him."
and from pg 26:
"Even those who seemed so impressive upon their much anticipated arrivals, such as the raucous buckskin-clad riflemen from Pennsylvania wound up disappointing the rest of the recruits in the army. They turned out to be chaotic bands of untamed frontiersmen who unnerved all who met them. They cursed throughout the day, drank as often as they worked, disdained the men from Massachusetts, and paid little attention to the rules of the newly created army. On two occasions in Boston, a group of them charged a guardhouse and freed their compatriot Pennsylvanians who were incarcerated there. Emboldened by their success, the riflemen tried a third rescue, but Washington heard of it an surrounded the guardhouse with five hundred men, muskets loaded, and told them to shoot any riflemen who approached. None did."
and
"One officer complained about them that there never was a more mutinous and undisciplined set of villains that bred disturbance in any camp".
pg 26 quotes used by Chadwick came from
Rebels and Redcoats by Scheer and Rankin.