What change in the construction of rifles the americans during the revolutionary war?

The main change in the construction of rifles that helped the Americans during the Revolutionary War was an "increase in barrel length," since this longer length helped the colonists fire at the British from longer ranges. 

The lengthening of the barrel and the transition from muskets to rifles. The longer barrel helped with accuracy. With rifles, the US could fire at the British from a safe distance and with accuracy.

In 911, a group of vikings lead by rollo besieged paris and chartres. after a victory near chartres on 26 august, charles decided to negotiate with rollo. the talks were led by hervé, the archbishop of reims. this resulted in the treaty of saint-clair-sur-epte, which granted rollo and his soldiers all the land between the river epte and the sea. it also granted him brittany, "for his livelihood". at the time, brittany was an independent land which france had not been able to conquer. in exchange, rollo promised the king his loyalty and military assistance when needed. also rollo also agreed to be baptised and to marry gisela, the king's daughter. the territory given rollo is about the same as upper normandy. this would grow to become normandy under rollo's descendants. - wikepedia