Slipper,
When you say high magnification,how high would you like it to be? Are there any other considerations regarding magnification range, tube diameter, objective size as well as parallax adjustment? Do you need a BDC turret or BDC reticle for a specific 223 load?
How much are you looking to invest?
I have been involved in shooting industry in Canada for 9 years and have dealt with questions like yours on daily basis.
Hope I can be of help.
Best regards,
D.