Thanks for the weight and wall-thickness survey, Ed. So much for my raw mass theory!

As the specs you posted show, cartridge brass is a pretty simple alloy, around 70/30 copper/zinc with low levels of allowable impurities. It's a standardized product the ammo makers buy in huge rolls from the brass mills. If there's a difference in the quality of finished cases lately, I suspect much of it arises during their manufacture - whether from changing the number or rate of draw operations to speed production or maybe skipping some annealing (saving energy?) is certainly beyond my limited knowledge. No evidence, I'm just trying to apply a little logic to the question.

Fortunately (thanks to reduced loads and castor oil ), I'm still using a few of the WRA-43 cases I first reloaded in 1958 and have many others that are "only" 20 or 30 years old. It's unlikely I'll ever need to buy more since "lifetime supply" is becoming a smaller quantity with each added candle on the birthday cake.