My CZ-75B has the factory standard spring - 14-lbs I believe for reference's sake. Also note as well that it has a 4.7" barrel.
my Winchester 231 Data:
3.6 grains yielded 978 fps at COL of 1.050"
3.8 grains yielded 1036 fps at COL of 1.050"
4.0 grains yielded 1062 fps at COL of 1.050"**
4.2 grains yielded 1099 fps at COL of 1.050"**
4.4 grains yielded 1137 fps at COL of 1.050" - at which point leading started to increase significantly.
The most accurate load in my pistol for 231 (and altogether) was the 4.0-4.2 range. The 3.6 grain load did not reliably cycle my pistol, with brass hanging up every 5-6 shots. I set to 4.1gr in my powder dropper, +/- the tenth of a grain I can count on in the Lyman #55 to land me in that 4.0-4.2 range either way.
my Hodgdon HS-6 Data:
5.5 grains yielded 1002 fps at COL of 1.050"
5.8 grains yielded 1069 fps at COL of 1.050"
6.1 grains yielded 1144 fps at COL of 1.050"**
6.4 grains yielded 1207 fps at COL of 1.050" - again at this point leading started to increase significantly.
For HS-6, which is my 2nd favorite/most accurate 9mm cast powder, the 6.1 grain load right before leading starts gives me the most consistent benched groups.
I didn't PM the Blue Dot Data, but here it is:
6.7 grains yielded 1091 fps at COL of 1.050"
7.0 grains yielded 1154 fps at COL of 1.050"
7.3 grains yielded 1196 fps at COL of 1.050"**
7.6 grains yielded 1246 fps at COL of 1.050" - interestingly still LITTLE leading but the brass was really starting to fly and the charge was, I believe, compressed
Blue Dot obviously runs okay in my 9mm pistol, but I don't like the way it burns - behind some bullets it just won't burn completely at all. It does have the advantage of being slow, which helps with leading/pressure I think because those ~1250fps buck but they don't lead badly.
**Most accurate load in a given powder.
Oh yeah, my bullets are lubed with a hard, blue waxy type and test around 21-22 BHN always on the Lee Hardness tester.
THESE LOADS, ALTHOUGH NOT MAX IN MOST CASES ACCORDING TO FACTORY DATA, WAS SAFE IN MY PISTOL BUT MAY NOT BE IN YOURS. USE LOAD DATA AT YOUR OWN RISK AND WORK UP LOADS CAREFULLY, CHECKING FOR SIGNS OF PRESSURE ALONG THE WAY. DO NOT RISK LOSING A HAND OR WORSE BY ASSUMING YOUR EXPERIENCES WILL BE THE SAME AS MINE. YOU'VE BEEN WARNED.
I've got the SR-4756 data slipped into a loading book somewhere, one that may have been borrowed actually. I'll look all over for it but I won't extrapolate off of memory there.
Any interest in the same sort of data for 115 rainiers or Win/Magtech FMJ's of the same weight, I've got an excel spreadsheet working that I keep most of my data and a lot of "geek stats" on.
Again, which will happen occasionally, apologies on the long post.