What did Johnny trade for a muskett? Who did he trade with?

Johnny trades with Pumpkin, a very reluctant British soldier. Pumpkin wants to leave the army and blend in with the locals,

"When (he can get him) a smock such as farmers wear. When (he can get him) an old hat with black hair sewed in it, hanging down...when (he can get) a farmer who'll swear (he's) his hired man and can take (him) out past (the) guard on the Neck."

In exchange Johnny gets a muskett.