CLean97,
I believe you are mistaken about S&W and the .38-44 load.
Elmer KEITH developed some really hot loads for the .38 Special in the 1930's and wrote about it. When S&W decided to bring out a hot loaded .38 Special, THEY DID NOT RECOMMEND THE K-FRAME Military & Police REVOLVER TO USE THIS AMMO. They took their larger N-frame revolver which normally was chambered for the .44 Special cartridge and chambered it for the .38 Special. They labeled it the 38-44 because it was a larger, heavier, stronger .44 caliber gun chambered for this hot .38 Special load.
They later did the same thing when the introduced the .357 magnum, using the large N-frame instead of the K-frame.
COLT had a little advantage here. Their midsize revolver had not been designed for a .38 size round, but for the larger .41 Long Colt round which had been very popular for COLT in the late 19th century. This larger size gave COLT the confidence to claim that their .41 caliber, mid size revolver could handle the .38-44 while S&W did not think it was safe in the K-frame.
Since my personal experience with model 19's has not been positive, I suspect S&W was right in the first place.
As to downloading ammo, let's understand that a 1920's pressure measurement was not anywhere near as accurate as a 2020 measurement. Also, we know that many of the velocities listed in catalogs were taken with pressure barrels which did not have a cylinder gap and could be 6 or even 8 inches long. Also, those old loads almost always used lead bullets instead of jacketed ones. You can usually get higher velocities with lead ammo due to lower friction with the inside of the barrel when fired. Harder jacket material causes more friction or resistance to passing through the barrel when fired.
Also, please note that BUFFALO BORE is not a member of SAAMI, the ammunition industry standardizing group. So how do you know that their ammo is within industry standards.
Also, law enforcement agencies found that even +P ammo, when used regularly, in K-frame revolvers could damage them. They were designed for a specific pressure and recoil level. The metallurgy is better now, but the design is still the same.
Look at the difference in the top strap of the RUGER Security Six and the S&W model 19/66 and tell my which one is built to take higher pressure loads.
Jim