The big disappointment in the .41 Magnum came because it was not the gun/cartridge combination so desired by law enforcement officers of the time.
The gun they dreamed of was one to replace the .38 Special/.357 Magnum revolvers then in use, notably the K- Framed Smiths and Colt's medium framed Troopers and Official Police revovlers.
What would have been an ideal cartridge would have been a .40 or .41 caliber cartridge that could have been built on these frame sizes. Something just a like the current .40 S&W or similar round that maybe could be handled in, say, an L-Framed Smith.
The .41 Magnum was too much for urban police use, and the N-Frame too heavy for most daily police routine.
Fine as it is, the .41 Magnum just missed the targeted market.