Actually the Treasury load had a good track record and is still an excellent load. It's not for airweights at all. I've probably shot close to 3 or 4 hundred rounds from an early 640 with no ill effects whatsoever.
The specs. were 1,000 fps from a 2" tube which it easily met. I believe the pressure was held around 23,000. I would suspect you would get around 1150 from a 4".
Corbon's original +P load was hotter than the Treasury load and I'm sure there were "problems" as their current .38 ammo is not as hot.