As best you can, please describe why the GP 5-shot .44-caliber revolver is not — was not — available in 44 Magnum?

I believe the length of the cylinder window is a factor.

My understanding is that they would have to lengthen the frame to fit the extra length of the mag. round.The current frame fits many variations now and it would be retooling to fit a mag. and for just one design.This is my understanding of why,from the Ruger forum.

With BUFFALO BORE heavy .44 S&W SPLs (which the beefy GP loves and howls for more) you don't give up too much.

Many thanks. I just verified SAAMI specifications for 357 Magnum — that is, GP1xx's original reason for "being" — and 44 Magnum. The COAL for the 44 is precisely .010 inch longer than the 357. While a hundredth of an inch sounds like a "no sweat" change to me, in the real world it must be a show stopper,