One of the best books I've ever read (and trained with) on shooting the Enfield rifle is available in electronic format, professionally scanned (thanks to Ian Robertson), in the Knowledge Librarysection Technical Articles for Milsurp Collectors and Re-loaders (click here)
"Shoot-to-Live" - 1945 (click here)
Presenting the Johnson Method of Musketry Coaching As Adopted By the CanadianArmy, Ottawa, Chief of the General Staff.
This is an excellent Canadian Government issued training manual. If you are specifically a collector and shooter of Lee Enfield Rifles, you'll find this to be an outstanding reference work and it contains a wealth of information on how to properly shoot the No.4 Mk1 Enfield, although much of the content is applicable to any bolt action rifle. I remember being issued this manual as part of our regimental rifle team, when I was a little younger back in the early 60's.
Regards,
Doug