DUCKBRX,
Unfortunately the minimum focus distance on that scope is supposed to be 50yds. You'll always get a little closer than what we advertise, but I doubt it will give you a clear picture at 15yds, especially since you cannot reduce the magnification.
One possible way to help this would be to use an F-stop. The easiest way to do this would be to pick up a simple inexpensive objective lens cover and punch a small hole in the front, probably about 1/4-1/2". This effectively reduces the size of your objective lens and will reduce the effects of parallax and improve focus at distances closer than your scope is focused for. This will of course make your image a bit darker, but that may not be an issue for competition use.
In the future, you might look at the VX-Freedom 3-9x33mm EFR (Extended Focus Range). This scope has a special AO that will focus down to about 10yds and would be a great fit for a competition rimfire. Hope this helps, and give us a ring if you have any questions!
