The only issue I had, and it wasn't much of a problem, was slick Delrin not gripping very well on a gloss finished Leupy. It did fine with matte finished scopes. I stuck a strip of blue painters tape in the inside "V" of the Reticle-Tru and the extra friction held without slippage.
Aligning the reticle with the slit is easy if one holds the scope to the light and moves one's eye back and forth to precisely align the edge of the slit with the reticle.
