When I started handloading ~17 years ago I worked up overloads with every 9mm bullet and powder.
I have many 9mm handguns. The typical unsupported case wall over the feed ramp is 0.19".
The case webs are 0.16".
The net thin unsupported case wall in 0.030". The case wall is ~0.15" thick that bridges the abyss.
This situation or better is found in almost all 9mm pistols. I cannot get enough Unique to fit in the case with any bullet to make a case bulge.
Unique lacks the speed * density product to make pressure trouble. There can still be too much recoil, cases fly too far, and the slide hammers the frame, but no pressure problems.
Pressure problems are easy to achieve with AA#5, 3N37, and HS-6. They have the speed* density product.
Pressure problems are easy to achieve in barrels where someone put a Cratex abrasive tool in a Dremel and polished the feed ramp down to where the case support is compromised.
