You are welcome to post your ADI 9x25 workups here! It would be interesting if you know the comparable powder in the US...
I use Winchester (Non-Nickel) Brass. I have had similar (split neck) failure rates with Remington Nickel Plated brass. I think the Nickel Plated stuff is strong, but too brittle to handle the re-forming for very many loading cycles. The Dillon dies are for forming, and really work the brass hard.
With Winchester brass, it takes several loadings to see head separation, or loose primers.
I would like to find some 10mm brass with SMALL primer pockets to see if my loose primer problem goes away...
I have a different purpose for 9x25 than some others. I shoot mine exclusively from my 3.8" G29 barrel. Concealed carry + velocity is what I seek...
If I were playing with 135+ grain bullets, I would stick with regular 10mm. I can actually get better velocity in similar bullet weights in 10mm compared to 9x25.
Are you doing Things Right?
Or doing the Right Things?