The Kimber magazines do not work in the Sig 1911. The reason is the Kimber mags are plastic and too thick, dont even fit in the magwell of the Sig. I can see the Sig 1911/GSG 1911 mags fitting in the Kimber loosely though. The basic geometry looks the same on both mags. The Kimber mags look to be very similar if not identical to the Marvell Precision magazines.
Perfect!!! RRages cancelled my order and the Sig mags were $45. Another store had the Kimbers in stock for $22. i took the savings and order a few mags for my 41 Thanks buddy!