I need to find a place that will sell me about 10 of each so I can see which one shoots better out of my rifle...
Ten rounds isn't likely going to be enough to work up a load and then test it out to 500yards to confirm the accuracy.
If buying a whole box is too much of an expense for you,how much do you intend to spend every year practising so you are capable of good 500 yard accuracy with the rifle?