Ken,
Try neck sizing ,or set your full length die to size about the first 3/10" only. Just enough to grip the first 0.224" of the base of the bullet, or the maximum C.O.A.L. which ever fits your rifles chamber without jamming the bullet into the lands.
The Lee collet neck die is my favorite, I use it ALA Vern Humphery, with a couple washers dropped over the case onto the shell holder, that starts the collet closing early and only squeezes the very top portion of the case and leaves the rest undisturbed.
The Hornets case capacity is so small that primer brilliance, (the ability to ignite the powder) can make a big difference in accuracy. Some loaders have had good luck with small pistol primers or "benchrest" small rifle. I have found the CCI small rifle bench rest to work very well, along with Remington 6 1/2's, they both cut 0.25" off my groups with WSR's.
Lil'Gun with the 40 Vmax's gave me smaller groupings when I dropped the charge from 13grs down to 12.5 grs, again changes as small as 1/10th grain in that tiny case can cause big differences.
As posted by Spitzer224, bullet run out in that little long necked case is a big factor, try to keep it at a minimum. When I seat the bullet I start it into the case and then rotate the case in the shell holder 180 degrees then seat it deeper, turn again and then fully seat.
The RCBS Competetion seater Spitzer224 mentioned, and other seaters that are similar, hold the bullet in alignment with the case mouth to keep run out at a minimum.
Hope some of this helps.
dd