There aren't any "special" feed lips. There are only three types. The original tapered, late/gradual release or "Hardball" type. The parallel, early/abrupt type...called "Wadcutter" feed lips because they were intended to be used with SWC ammo...and the "Hybrid" type, which is a combination of the first two. It appeared in the early 80s, about the same time as the Series 80 Colts...and it was a Colt design.
By the way...I coined the term "Hybrid" when I was corresponding with Check Mate during the development of their 8-round patented Bullnose follower. I also gave them the design for a gauge to set the release point of their GI hardball magazines.
Here are the three types.
L-R Hardball Hybrid Wadcutter
The difference is in how and when the magazines release.
The full-tapered hardball type releases gradually, allowing the rear of the cartridge to move upward as it moves forward. This accomplishes two things. It reduces the angle of the cartridge as it enters the chamber, and it allows the rim to be picked up by the extractor while it's still under the control of the magazine.
This one will allow a round to be chambered slowly by riding the slide to battery. The "Wadcutter type won't allow that because the round releases and jumps ahead of the extractor. The "Hybrid" type will also allow slow chambering with hardball ammo and its longer OAL, and with the Hensley & Gibbs #68 bullet, but not with anything with shorter than about 1.235 inch OAL.
Pictured below illustrates the difference between a wadcutter and a hybrid. Here, both rims are against the backside of the bump in the follower, just before the final release point. If the magazine on the right were in a gun, the rim would already be started under the extractor, leaving it no place to go except where it's supposed to go in the unlikely event of a too-early release.
This defines "Controlled Feed." Under complete control from the instant that it moves until it's in the chamber. The early/abrupt release of the "Wadcutter" type often doesn't provide that, especially on the last round with a smooth-topped follower. That little dimple was put there for a specific reason.
The difference:
The Hybrid lips combine the best of both. It provides the controlled extractor pickup of the hardball type, with the earlier release point of the wadcutter type, but still slightly later and slightly less abruptly...reducing the chances of the round jumping ahead of the extractor...for use with short SWC and hollowpoint ammunition.