Query about a musket

[Lenny]

Dear Friends,
I attach two photographs of a musket that I recently acquired showing the butt and the lock. I will post an overall picture later...It is .75 calibre smooth bore, with the stamp 'Lon [indecipherable]on the plate. It has a flintlock mechanism, though the cock is missing. There is no apparent way of attaching a ring or socket bayonet because the wood under the barrel extends to within one quarter inch of the muzzle

I am guessing that it dates to about 1690-1700. What puzzles me is the size of this thing: 5 foot 8 inches from butt plate to muzzle which seems to be too big for a standard foot soldier's musket. Yet it is not ornate or even well finished enough to be a hunting weapon (I think) Any ideas?
Best,
Lenny