Have you tried the old M1 Rifle sighting target?  I've used them to get in the ball park.  Set target at 50 yds and use a 6 O'clock on the black circle at the bottom. For scopes, you sight with horizontal cross hair like a 6 O'clock hold.

I bought mine from National Target Company (ST-1) at:   (You need to Login


I could mail you a couple if you would like.

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