IMR 7828 is similar to R#22, and primer choice will have a great influence on the group size, start with cci 250, then fed 215....you never know what the barrel will like...humbling.
Ann, if you can find any R#26 with a cci 250 or Fed 215, you will be all over 3100-3150 fps at the accuracy node, do not use Federal, norma, or Nosler brass for this load(soft case head).