Re> 100 Sierra 45gr Hornet bullets
Which 40gr Sierra bullets? The Sierra #1100 Hornet bullets are intended for early Hornets that used a .222/.223 bore diameter. Your modern Ruger will work beter with the .224 Sierra #1200 bullets.
Use a modern manual that shows loads for both. My older Speer #9 lists "one size fits all" data and is several grains below the Hornet's potential.
Also, the origial offerings of the Hornet used a 1-16" twist that worked best with only the lightest of flatbase bullets. The faster twist on Ruger will stabilize a wider range of bullet designs and weights. That may matter to you if you plan to hunt groundhogs on windy days.
I've only been loading since last year and have had excellent results with both the 45gr Nosler and the 40gr Nosler BT. 2400, H100, and IMR 4198 powder are all capable of giving woodchucks headaches at 200 yards.
I haven'texperimented with anything other than small rifle primers yet.