Blacken the mag with Dykem or a Magic Marker. Slide it in and out a few times and look for rub marks. Normal causes are long grip screw bushings/screws, trigger bow or the tab on the bottom of the sear spring protruding into the mag well as well as what jjfitch pointed out. Once in a while the mag catch will depress in far enough it can trap the magazine if you mash it in as far as it can go. Also look for cracks on the rear of the feed lips. Have these magazines been dropped onto a hard deck repeatedly?
A smooth cut fie will bring the bushings down to proper length easily without removing them. If the bushings are too long you will continue to find magazines that will hang up. The problem is not the magazines - it's the gun. Any magazine made should fall out of the frame.
Well if you insist on using junk magazines (Kimber) then you will have problems. My Taurus uses all mags except Kimber because I finally figured out Kimber magazines rarely worked in anything, if they worked at all, and life is too short to use junk magazines.
It's not so much that they're "junk" - they just don't fit in your frame. Tolerances today get sloppy to meet production goals. Everything on a 1911 has to be sized to fit your frame - including magazines and ammo. You only get away with a tiny bit of + and - and things get too loose or too tight.
My Dad has a Taurus PT1911 and it did the same thing. It is indeed the gun, not the mags. I tried every 45 mag I own (about 50 of them) from all manor of makers and only the mags that came with it did so without issue. By comparison the Colt, Ruger, Springfield and SIG 1911's I owned at the time would drop all those mags freely. Also at work we have two PT1911's and one of those drops any mag, the other hangs up like Dads gun. It is an easy fix as described. Its a shame a new gun needs "Fixing".....but many do.
Miraculously Dads PT1911 is one of the most accurate 1911's I have ever had the pleasure to shoot. It at least has that going for it.
Bushings protruding into the magwell is not just an issue with Taurus. I have seen this on many other brands of guns. It's just one of those things that you must check on any gun unfortunately. You should also always check to see if the bottom front of the disconnector is protruding into the magwell. On any brand. You should be able to assume that your new gun is in spec but sadly many are not.