Rather ridiculous that the Allenberger book has 2500+ reviews on Amazon and the "Voices of RussianSnipers" has precisely one. Allenberger is useful for the window it provides into the typical mentality of the type. Apparently he took up sniping as a sport with a captured Soviet rifle at the outset.
The Shanina book is poorly reviewed as being mostly a recounting of personal relationships and that of only about six months total coverage.