This....you load for the caliber/cartridge, not the platform. The platforms are designed for the caliber/cartridge.
That's ONE way to do it. Another way is to load for the caliber/cartridge, AND the "platform" (the gun).
A couple of examples of that are "Ruger Only" .45 Colt loads, and the three tier load levels used for the different strength levels of .45-70 rifles.
The "platforms" vary. Both by design features and strengths, and as individual units. You can load to a standard that works in multiple guns in the same caliber, and its not a bad idea, but doing that leaves you unable to take fullest advantage of some guns abilities.
Both approaches have their pros and cons.
And, I would point out that every load in the manual isn't suitable for every gun out there. I've shot loads listed in the manual, same load listed in both pistol and rifle sections, there were not suitable for all the guns I had. Shot a hot .357 load from a K frame, and N frame, a Desert Eagle, and a Marlin carbine. Fine is the big guns and the carbine, the K frame needed to have the empties driven out of the chambers. Was smart enough not to even try that load in a J frame gun.
If you have guns that cover a wide range of capabilities to feed, loading rounds that work is all of them is a good practice, ensuring you won't get the "wrong" ammo in the wrong gun. Lowest common denominator works.
Tailoring ammo to each specific guns strengths and weaknesses requires more work, and keeping ammo segregated for safety reasons, for some of its the way to go.