https://www.gunsandammo.com/editorial/ruger-super-gp100-9mm-revolver-review/382947
"In 2014, the USPSA amended its revolver rules to allow for a capacity of up to eight rounds, which made most traditional revolvers obsolete for these matches. Eight-round revolvers all fall into the “minor power-factor” category, which means the 9mm sits in its mild-recoiling sweet spot without having to push the pressure envelope. If an individual is interested in competing in the USPSA Revolver Division, the new Super GP100 in 9mm is a turnkey solution."
"Though it has an effective barrel length of 6 inches, only 43/4 inches of barrel extends forward of the frame. The reason for this is that the 9mm cylinder is appreciably shorter than the frame window, allowing the barrel to extend well inside the frame to mate with the cylinder’s leading edge."
Ruger Super GP100 Competition 9mm Revolver (2020):
https://www.americanrifleman.org/content/review-ruger-super-gp100-competition-9mm-revolver/
"Like other members of the GP100 family, the Super GP100 is a double-action revolver with a transfer-bar safety and a cylinder that locks up in three locations (front, rear and bottom) for improved alignment and durability. However, this particular model is built around a Redhawk action. This provides the frame space needed for the larger diameter of the eight-round cylinder and a two-spring lock work configuration for improved cartridge ignition and smoother double-action cycling."
"While some shooting enthusiasts may argue the usefulness or limitations of moon clips when used in defensive revolvers, their utility is clearly evident in a competition gun like this one. Because the 9 mm cartridge has no rim, they are headspaced off of the cartridge-case mouth in each chamber of the Super GP100's cylinder. This means the revolver can be safely loaded and fired without a moon clip.
However, these semi-auto cartridges have no rims for the ejector star to press against in order to kick out the empty cases, so each case must be poked out of the cylinder manually with a cleaning rod or similar tool. This revolver arrives with three full moon clips which literally clip into the groove at the base of the cartridges to align them with the chambers of the cylinder. This allows all eight rounds to be dropped into the cylinder at once."
Still easy to find used at around $1,500.