I just loaded up and shot a dozen test rounds from a Glock 21sf based 9x25. 10.2 grains AA#7, 115 gr FMJ, 1.275 col. it's a snappy fun round based on 10mm. It's like a big .357 sig.

Now I need to load up a bunch more.

Next stop .400 corbon.

Did you chronograph them to see how fast they were moving?

No function test for the gun and my die setup. Going to up the load a touch and then chronograph.

10.6 grains for AA #7 with 115 grain bullet (gonna try 95 for real velocity) and I got 1687 fps.  I think I can get a touch more because I'm on the low end of the load data and no pressure signs at all.  

 

I think with 95 grain I can get close to 2k fps.  

 

I loaded some 400 CorBon for a 1911 I have but forgot the ammo at home, dope, so I didn't get to try it after thinking about it all night and not sleeping well because of it!

 

My custom Glock 9x25 nice extended slide with further extended barrel for nice velocity.