Spend the $15 and buy some good Wolfe Springs.

If you plan on shooting big heavy bullets a Ken power pawl may be in order.

You are spot on with the throat work. I have a buddy in NC that has a jig grinder. He does mine they come back closer than I can measure with a bore mic. He says they are within .0002"

Try a 250 XTP with 20.5 of 2400 and a CCI 350. You will not be disappointed.