Given that the IDPA is experiencing so much change currently, along with significant personnel changes along with the relocation of their membership headquarters, there is been a fair number rule changes that I am not completely up to speed on. I typically shoot SSP as a sharpshooter. Regarding the box, yes an empty mag has to be in the gun. Assuming you're shooting 45 ACP in CDP. Technically, you could shoot to Mccormicks, but you would not be able to load them to capacity but rather division capacity, and further, with the McCormick's inserted a 1911 would not fit in a box. Also, in IDPA (similar to US PSA production), you're much better off for speed of the draw purposes to buy high-quality outside the waistband holster from a company like Comptac for Bladetech and edition a lot of new high-quality holster makers also have product on the scene, in contrast, the Uncle Mike's brand holster, is listed by name in the IDP rule book and specifically prohibited.(Further, although USPSA permits a dropped an offset holster hanger, IDPA does not and lists specific measurement for the amount of maximum drop a holster can have, as well as how far horizontally off the hip the holster can be (just go to the IDPA website and download the rule book for free). Most factory 45 ACP we'll make power factor, since all targets are engaged with a minimum two shots in most courses is a fire, finding that factory round that consistently we'll put you just above division power factor, is the best route to take. If your intention is to be competitive, it probably doesn't make sense because of the cost as well as increased recoil, it's best to steer clear of hot defense loads, but rather shoot something like Winchester white box, or Federal American Eagle, etc. I don't have a clear recollection regarding appendix Carry, but I believe in the past it was prohibited and whether they've begun to allow it, I don't know. And lastly of course you can carry Booth inside the waistband and outside the waistband in the 3 o'clock and 9 o'clock positions as well as the small of the back positions without drawing the ire of other shooters or safety officer. Finally, don't forget a concealment garment unless the match you're shooting is specifically waiving the need for one.
Thanks
Jon