Like Gotbuck, I do the same thing. Only believe this or not, set the rifle in a cradle. Even a cardboard box can be used if you have nothing else. I bore sight at 13 yards and set the BDC to 0. Then set the cross hairs to the bore.

Then go shoot at 25 yards and you should be very close. Then all you do is set your scope to the distance you want and work off there.

The other night a person in IM was asking me about the BDC on the same scope as you purchased. They asked if it was worth getting. I told them I have a scope on a modern centerfire with a BDC and have never used the thing... I sighted the rifle in the way I wanted and have just shot it from there. I was always worried that the BDC would not be accurate.

You've got some good information on here from Sabot loader and others. Try that out and let us know what happens.