If your powder charges are below 50 grs, and you are not going to use the rifle when the temperature drops below zero degrees fahrenheit, the standard primers will be fine. If the ammo is going to be used in extreme cold, it wouldn't hurt to use a magnum primer.
The use of a magnum primer might result in a little loss of accuracy, or it might not - there are many variables. The magnum primer is stronger, so the ignition of the powder column will be more violent and there could be an increase in pressure. If the increased pressure created by the magnum primers has a detrimental effects your rifle's accuracy, you must determine if the trade off between the loss of accuracy and the benefit of more consistent ignition is worth while. I think that for the cost of a 100 primers it is a worth while experiment.