The 38/44 loads were less .38+p, and more .357 Mag for pressures.
+1. However, it should be emphasized that nobody is really certain about the operating pressures of the .38/44 (aka .38 Special Hi-Speed) cartridge. There was no organization overseeing and regulating cartridge specifications in the late 1920s when this cartridge was introduced. What's known about the .38/44 today was mostly determined by firing vintage .38/44 loads through .357 Magnum revolvers, measuring the velocities, and back-calculating the pressures using ballistic software. This method is only good for rough approximations.
Furthermore, society from the 1920s to the 1940s was far less litigious than today. Many companies, including but not limited to gun manufacturers, made claims about their products that range from questionable to downright ludicrous by today's standards. ("Top Athletes use {insert brand name} Cigarettes- They're a Lighter, Healthier, More Satisfying Smoke!")
The
only thing that's for certain about the .38/44 cartridge is that the revolvers designed for it- the S&W .38/44 Heavy Duty and .38/44 Outdoorsman- are ridiculously overbuilt. They have extremely thick cylinder walls, and many have been converted to .357 Magnum in past years without any ill effects.
I would not hang my hat on
anything Colt claimed about the .38/44 "back in the day". I would
not trust.38/44 ammo in a Colt OP or a S&W Model 10 / .38 M&P.