I have used it in .40 after reading Brian Enos forum recipes. From what I remember it is sometimes used to make major in most calibers. I find it .. well .. major! and am not loading it in anything less than 10mm anymore, I found other powders .
800X is a large grain cut powder. With the small amount that is used in 9MM your Lee measure will not like it and you will most likely have a large variance in your dropped charges.
800X is generally accurate in handgun loads it is also a very dirty powder to shoot.
There are better powders to use for 9MM. 231, #2, #5, bullseye, Unique, Ect.......
I second all three of those suggestions. I've been using Bullseye for 3 years but just wasn't happy with it. Seemed "finicky" to me.
I happened to have a probably 20 year old can of HP38 and tried some test loads the other day, it did well in all the bullets I tried at several different loads for each. Bullseye seems to have a more narrow performance window (maybe its just me). I also tried WSF and was happy with it as well.
Now I need to find someone local that wants to trade Bullseye and Unique for HP38/Win231. I can't get unique to meter under 4.8-5 grains.
Interesting about Unique powder, I have a few Dillon measures, A RCBS Uniflow a Lyman 55 and a Harold Culver Measure and all of them meter Unique just fine.
I've thought about getting a different measure, but Unique is the only powder I've tried that doesn't meter great for me.
My friend has a Uniflow, I'll give it a try.
I use the 800x for my 10mm right now I just loaded up some 180 grain gold dots with 8.3 grains and used my chronograph to check speeds. So far they averaged 1221 fps. which seems to be faster then some of my other powders with less in it. So far it works well, also I have had good luck with v.v. n-340 it meters very well and only uses 7 grain or so for a 180 grain GDHP I would think the the v.v. n-340 would work well with a 9mm also