Well, whats interesting is that none other then Jeff Quinn had the 10mm GP100 rechambered in 10mm Magnum, which is pretty close to .41 magnum.
https://gunblast.com/Ruger-GP100MC-10mm.htm
I sent it off to Tyler Gun Works in Texas to have the chambers lengthened to 10mm Magnum specifications. The 10mm Magnum is a stretched 10mm Auto case. It is longer, but all other dimensions are the same. The 10mm Magnum case is nominally .258 inch longer than the 10mm Auto case, which gives approximately one-quarter inch more room for powder! More powder equals more speed, and the 10mm Magnum can best the 10mm Auto velocities by between 150 to 300 feet-per-second (FPS), depending upon the bullet chosen. The longer case will also accommodate heavier bullets, if that is the preference. Using the moon clips provided with the GP-100, the revolver can now fire 40 Smith & Wesson, 10mm Auto, and 10mm Magnum ammunition.
http://smith-wessonforum.com/reloadi...onversion.html
Full load, per Quickload, puts the 10mm Magnum with 200gr @ 1400-1500fps from a 6" barrel (~ equivalent to a 4.2" revolver barrel + 1.59" cylinder). This is comparable to a 200gr .41 mganum load.
Ideally, Ruger could come out with the '.40 Magnum' or 'Ruger .400 Magnum' to make this a factory revolver.
Take the 10mm Magnum case, lengthen it from 1.255" to 1.290" (same case length as .357 and .41 mag) and slap a rim on it. Pressure could either be standard 10mm Auto/Magnum 37kpsi, or ideally, bump it up to 45kpsi ala .327 Federal.
This cartridge would be a very attractive magnum. 200gr @ 1400fps+ from a 4.2" GP100, with ability to fire 40s&w and 10mm using moonclips as 'specials.'