OK, apologies for this taking so long, this being retired is more difficult than it at first seems.
Good news I did the water jug tests with spectacular results. Bad news, I am having trouble transferring the pictures.
To the report; the Berry's plated HP over a stout load (1264 fps from a 4" Model 66) of 17.5 grains of Lil Gun penetrated into the 5th gallon water jug, however the whole nose of the bullet was sheared off leaving only a .357 cylinder (103 gr). The only plating remaining was a dot where the HP hole had been.
I did not believe the results so redid this with the same results.
I tried a Hornady XTP, as a comparison. This was a hot load of 158 gr XTP over 16.6 of 296. This generated 1217 fps from a 4" 66 and 1809 fps from a Marlin 1894. The XTP mushroomed beautifully, to .540" and retained 142 gr of weight. Really a beautiful bullet design, all 6 jacket petals peeled back and the soft core mushroomed out. It also penetrated into the 5th jug of water, so it would seem that the energy expended tearing the nose off the Berry's was approximately the same as that required to mushroom the Hornady??
These were both loaded in .357 Mag cases, as I do not think you can get 1200 fps from a .38, not even with "The Load".
Conclusions; not sure if there exists a sweet spot where the Berry's would upset and expand without tearing apart? I am sure that the Hornady is one extremely well designed bullet. I shoot 3 or 4 thousand Berry's plated bullets for IDPA and load 1 or 2 K more for my son in law, I like them for what they are, but I don't think one should expect them to expand.
I haven't given up on the pictures, but wanted to send something for now.