Forgot this paper based on drill manuals
H. Kleinschmidt, 1999, 'Using the Gun: Manual Drill and the
Proliferation of Portable Firearms', /Journal of Military History/
63iii, pp. 601-630.
There are also a vein of recent research by Sandhurst historians
contrasting manuals with actuality of mostly C20 warfare but I am not
very familiar with it.