I used it for 38 and 357 loads with lead and jacket bullets. (SR4756)
It really sucked in my 38 spl. 1 7/8 inch snub nose except for a low velosity target load with the Mag-Tech 158gr LRN bullet.
It gave fair groups in the 686 6" with 38 brass but nothing that out grouped my other powders. It also worked better with the heavier bullets and 5.8grs of SR4756 with a cci500 primer got me a +P velosity.
With the Magnum loads light loads with a 110 jhp had a +/- 367 fps difference,probably due to the primer going across the top of the powder with the Hodgdon data.
the 125 Jhp shot better and a standard 1448fps can be attained with as little as 39fps ED's but pressure spikes happen at maximum loads and with primer changes, take care if using the cci550 primer,which is not needed for this powder.
the 158 XTP really worked well with this powder and I had no problem with my first try finding a fac dup of 1235fps with an ES of only 44 fps with a cci500 .
It is not mentioned in the manuals but I think a 60% case density w/bullet seated may be needed and a chrony sure helps out when you are getting near maximum loads. With its small size and density a little dab can make your scale move,big time so you need to weigh your loads,one of the pains with this powder, but it will deliver maximum velositys ,if thats what you want.
PS;
I have yet to find a manual with data that fits "Todays" SR 4756 per barrel length/fps that comes across my chrony at eight feet. Most max loads are standard 38 spl loads for the j frame except the new Lyman for 38,357,44&45 colt comes the closest to my test and readings.
Stay safe.