CAUTION: The following post includes loading data beyond currently published maximums for this cartridge. USE AT YOUR OWN RISK. Neither the writer, The Firing Line, nor the staff of TFL assume any liability for any damage or injury resulting from use of this information.
I did some experimental work ups in my Kel-Tec P32 32acp.
The case web is only .15" thick and the feed ramp intruded .25", so with .1" of thin unsupported case wall, I should get guppy belly case bulges a little over max published loads, right? Wrong. The inside diameter of the case is small, so the stress is small.
I was told that the tangential stress in the wall of an infinitely long tube would be s= [inside diameter][pressure]/ [2[wall thickness]].
I asked my father, a chief engineer over 150 engineers and draftsmen designing military guns and vehicles for 40 years, how he knew that. He yelled at me, "BY INSPECTION!".
What does all that mean?
I could put double loads in the poor support P32 and still ok.
If I welded up the feed ramp, I could put triple loads in there.
But with a muzzle extension, a welded feed ramp, triple loads and 110 gr [heavy] bullets, the biggest recoil springs that would fit were not enough, and I sheared off the ejector in the P32. Too much recoil for the tiny gun.
So when I found an old heavy Spanish 32acp for $30 with no magazine, I made a different old magazine fit by milling out a large bottom plate.
I measured the chamber support by putting an empty case in the chamber and scribing an outline of the feed ramp with a needle. I measured the chamber wall thickness. I knew this 80 year old piece of junk could take some extreme pressure on the first shot. No work up needed. Risk is the unknown, and I could see the future.
I was right about the pressure, but maybe milling parts and handloading 32acp was not the best use of my time.