Well, as you no doubt know, the DGW catalog has proof-load tables in the back, which show whatthe proof load for various gauges was back in the 19th century -if I recall correctly, these are British proof loads (and perhaps some Belgian). But again, it doesn't describe what to look for AFTER the load is fired!

Another problem is that our powders today are different from those used when those proof tables were developed. And who know how much different!