Hi,
According to data for several regiments published by Don Hagist for British troops during the Rev War period, the average height was 5' 7 1/2". Today in the UK, the average height of a white male is about 5' 10". Hagist published the data because it showed that the tall guys were put in the grenadier companies and the smaller guys tended to be in the light companies. British troops frequently remarked how much taller American soldiers seemed. I think diet had a lot to do with it. Clothing shrinks a lot over time so looking at museum examples can be misleading. I've measured a lot of British flintlock military and sporting guns. The length of pull varied from 13" to just under 14". The average for both groups combined was 13 5/8". I found it interesting that the shortest LOP (13 1/8") for a military gun was the pattern 1760 light infantry carbine. A gun for the little guys. In addition, the dragoon carbines I've measured had LOPs about 13/14", again guns for little guys on horseback. The long land muskets were all 13 3/4" - 14".
dave