The Galco Great Alaskan Leather Chest Holsters at the link below will fit that revolver.
https://www.opticsplanet.com/galco-great-alaskan-shoulder-system.html?_iv_parent-gun-model=smith-and-wesson-model-629&_iv_gun-model=colt-king-cobra-4in,colt-king-cobra-4in-pre-2019,colt-king-cobra-6in,colt-king-cobra-6in-pre-2019,colt-python-4in,colt-python-6in,colt-trooper-4in,dan-wesson-dot-357-4in,ruger-gp100-revolver-4-dot-2in,ruger-gp100-revolver-4in,ruger-gp100-revolver-6in,ruger-redhawk-4in,ruger-super-redhawk-alaskan-2-dot-5in,smith-and-wesson-model-27-n-frame-revolver-4in,smith-and-wesson-model-27-n-frame-revolver-6in,smith-and-wesson-model-28-n-frame-revolver-4in,smith-and-wesson-model-28-n-frame-revolver-6in,smith-and-wesson-model-29-n-frame-revolver-4in,smith-and-wesson-model-29-n-frame-revolver-6-dot-5in,smith-and-wesson-model-29-n-frame-revolver-6in,smith-and-wesson-model-325-n-frame-revolver-2-dot-5in,smith-and-wesson-model-327-n-frame-revolver-2-dot-5in,smith-and-wesson-model-327-n-frame-revolver-4in,smith-and-wesson-model-329-n-frame-revolver-4in,smith-and-wesson-model-586-l-frame-revolver-4in,smith-and-wesson-model-586-l-frame-revolver-6in,smith-and-wesson-model-629-n-frame-revolver-2-dot-5in,smith-and-wesson-model-629-n-frame-revolver-4in,smith-and-wesson-model-629-n-frame-revolver-6-dot-5in,smith-and-wesson-model-629-n-frame-revolver-6in,smith-and-wesson-model-686-l-frame-revolver-4in,smith-and-wesson-model-686-l-frame-revolver-6in,taurus-model-425-tracker-4in,taurus-model-627-tracker-4in
The holster at the link below might work with a Ruger Redhawk with a red dot.
https://www.opticsplanet.com/galco-kodiak-hunter-shoulder-holster-for-s-w-n-fr-29-8-3-8-right-hand-havana-kh130h.html?_iv_parent-gun-model=ruger-redhawk&_iv_code=GC-HT8-GALH-KH130H&_iv_gun-model=ruger-blackhawk-dot-44-7-dot-5in,ruger-blackhawk-dot-357-7-dot-5in,ruger-blackhawk-7-dot-5in,ruger-redhawk-7-dot-5in,ruger-redhawk-7-dot-5in-w-scope,ruger-super-blackhawk-dot-44-7-dot-5in,ruger-super-blackhawk-7-dot-5in-w-scope,ruger-super-redhawk-7-dot-5in,ruger-super-redhawk-7-dot-5in-w-scope,smith-and-wesson-model-29-n-frame-revolver-8-dot-375in,smith-and-wesson-model-629-n-frame-revolver-8-dot-375in
Thank you for your interest in our Great Alaskan Chest Holster. Yes, the Ruger Alaskan Right Handed fit for a 454 Casull is part number GA186 and is available through Optics Planet.
Thank you for your interest in our Great Alaskan Chest Holster. Our Great Alaskan Chest Holster is designed for large handguns, it will not fit the S&W M&P Shield in 40 S&W.