Not a lot out there on this powder besides 9mm Major and .38 Super.
VV lists two loads in .357 Magnum. Anyone try loading it in .38 Special? It appears that density and energy content in 3n38 is very similar to 3n37 with 3n38 being a bit slower burning. I'm looking at VV's load data for 3n37 in .38 Special and it looks like under a 160-grain LFN 5.3 grain start, 6.2 grain max.
Seems like ~5-grain start working up to 6.2 max would be plenty safe. Gun is a 4" GP100.
I know it isn't an ideal powder for loading .38 Special, but unfortunately, pickings are slim right now. I've got a backorder in for N320, but you know that's probably months away for delivery.
Might be useful:
VV 300-Series Powder Info