"RC, I think you are theorizing on the fly, with no backup facts."
Marco, you ever heard of working up a load? I've got almost 30 years of reloading experience s to draw from. How do guys use all that dirt cheap milsurp powder we've read about without published loads? Usually I say stick with published data especially for a newbie but if you know what you are doing, you can work up loads with suitable powders. I've personally used AA4100 in Ruger level 32 mag loads before 327 federal was a thing. 4100 is a 410 shotshell powder I picked it up on clearance for $10 a pound at a local shop and knew it would be similar to 296, H110 and 2400 because those are also 410 shotshell powders. Nobody else was thinking about the use of that powder for magnum pistol! I may not be able to point to a published recipe, but I am speaking from experience when I speak about powders that "may work" in 10mm and 44 magnum with loads that are worked up. I believe blue dot was originally a high base 20 gauge shotshell powder. Then people started using it in pistol loads. Now there is lots of pistol data for Blue Dot. Go figure..
WeWillie loves #9 in 10mm
https://www.glocktalk.com/threads/l...or-hot-10mm-and-rowland-even-magnums.1593650/
If #9 works well in hot 10mm, then 4100 will work in hot 10mm Too!
AA4100 and #9 are close in speed and you can use reduced #9 loads to start a 4100 work up. I'm sure handgun loads could be worked up for many shotgun powders that may not have published pistol load data.
Pro Reach is new that's why there is no pistol data...yet.. But we can look up pro reach and blue dot 20 gauge data to compare how they perform. For Pro Reach, 20.2 grains in Remington STS hull with 7/8 oz shot gives 1300fps. Now look at Blue Dot. 22 grains in STS hull for 1155fps. If I were to work up a handgun load using Pro Reach, I would start 1 to 2 grains below blue dot. I would see how much the powder filled the case and work up from there using my chronograph and inspecting my brass for signs of pressure. When powder gets scarce, the ones with the least data will be the ones left on the shelf.