And now that it's out of production (again), the .357 Coonan mags are around $200 each! If I ever get around to it, I may try a poor man's substitute (.400 CorBon or 10mm Auto ;>) to scratch my Coonan itch...
I don’t own one but I’ve put over 100 rds through one. 9x25mm Dillon. It’s a 10mm necked down to 9mm. pushed a 115 grain at 1800 ft/s and a 135 at 1700 ft/s. Over 800 ft/lbs with a very flat trajectory. Shot 3 Feral hogs and Coyote with it, one hog needed a second shot. You can run a 90 grain over 2100 ft/s, all from a 5 inch barrel.