I did load work-up testing today and I learned a few things. This will be long-winded, so the bottom line up front is:
230 grain Hornady HAP, loaded to a COAL of 1.220" with 7.0 grains of Silhouette from a 4.5" storm lake barrel in a Glock got an average of 760 fps at about 20˚F ambient temperature. It was miserable shooting weather, with wind, very light snow and about 20˚F temperature, so I didn't even bother to set up targets.
The Hornady 10th edition called for a COAL of 1.210", but these HAPs are from 2016 or 2017 and at 1.210" the brass extends past the bullet shoulder. This seemed odd, so I loaded them to 1.220", which takes the brass to the edge of the bullet shoulder but not past it.
Here's what I learned:
1. Standing outside in a wind, with light snow and 20˚F temperature, while trying to writing data in a log book... sucks. Bad.
2. Caldwell chronographs don't seem to like a little snow, 20˚F and/or how my shivering affected the bullets after they left the barrel; I got about 25% bad reads or errors. Conversely, in ideal summer conditions (70˚F and overcast skys), I normally have zero errors will this chronograph.
3. The Silhouette loads I made with 7.2 grains and up have a very stout, almost harsh, recoil. It would not be bothersome to someone familiar with shooting, but it was much more pronounced than most factory produced loads.
For comparison, I shot some Federal small primer 230 grain round nose under the same conditions and got an average around 715 fps.
If the weather is better tomorrow, I'll load some Long Shot and let you know what I find.