Here is what I got from SR 4756 out of my 6" 686 S&W MAGNUM revolver............
DO NOT use these loads, they are not published data,just my test that do not have pressure readings !!
As you can see this powder has a mind of its own.
Hornady 110 XTP with medium crimp all with Federal 100 primers.
6.2 grs 817 - 961 fps ES 144fps
6.6 grs 875 - 1135 es 260
7.5 grs 970 - 1056 es 86
8.0 grs 1179 - 1471 es 291
This last load is definately a "No,No" in a 38 special.
After testing a snubby S&W I found out that SR 4756 is too slow to work in these short barrels and is
only at its best in 6" barrels and maximum loads in steel frames or K frame guns or more, due to the
velosity jumps. Back to the drawing boards..............
Found out on the net that this powder is also "Position sensitive" and that a 60% case volume with a bullet loaded,will
help stabilise its FPS.............as you can see, my figures ,prove this out. I also used wspm, cci500 & 550 primers
with this powder, but thats another, story.