I shot one box of Winchester factory ammo through mine, but nothing but reloads since. I'm currently working through 500, 240gr SWC's, and have loaded them over WW231, Unique, IMR4227 (don't ask), and Ramshot Enforcer (don't do it). The brass is pretty fragile, has to be lubed before sizing, has to be trimmed about every other reloading, and you should use bullets of .427"-.428" rather than .429"-.430" diameter. Other than that, it's great! I don't shoot it more than 200-300 rounds per year, so the hassle of reloading is no big deal. Winchester 200gr. JFP ammo used to cost $25/box, but I think Cowboy Action has driven the price of factory ammo down considerably.
I shot an IDPA match, while the 5" barrel was still legal, but had to load it from a belt slide. Needless to say, the guy shooting a M1917 in "Relic Division", kicked my rear with his full-moon clip reloads. I want a rematch - do I have 'til the end of the month? - but need some speed.
A good load for the 240SWC is 7.5-8.5 grains of Unique.