col,I read they figured out the 38 Super accuracy problem "headspacing on the rim" way before 1950. I will try and find my source and post or maybe some one the board such as Mark from Colt could find out.
They may have figured it out in 1950. But like many other things (Beavertails, Commander style hammers, tighty fit slides and barrels, aluminum target triggers, dovetailed front sights, etc, ect) Colt probably didn't fix it in their production guns until 30 years later.
I can almost guarantee it was a series 80 improvement in the 38 supers.
38 Super headspace on case mouth. Guns magazine March 2001 issue, by Massad Ayoob.Quote "In the 70's Irv Stone @ Bar-Sto made barrels that headspaced on the case mouth,and the 38 Super's superb inherent accuracy at last came to light." another quote from article "It was Rob Leatham's pioneering use of the 38 Super to make IPSC major that led to the renaissance of this under-appreciated cartridge" End quote