Those who don’t believe Oswald shot President Kennedy point out that his Mannlicher-Carcano was not a very accurate rifle.  It didn’t even have a sight-adjustment mechanism, no windage or elevation screws.  True so far.  That’s why Oswald made sure to purchase a four-power telescopic sight with the rifle.  That scope did have the necessary horizontal and vertical adjustment screws, so crucial for ensuring accuracy.  And he used them skillfully.

CE541(3), from page 124 of The Final Truth: