Colt factory magazine. This mag uses yet another split, dimpled follower, but its feed lips are tapered instead of parallel. This kind of magazine is sometimes referred to as a hybrid magazine,
FWIW...Jackie Vieweg at Check-Mate Industries has credited yours ever-so-truly with coining the term "Hybrid" to describe the tapered/gradual release lip design. I know...That and a quarter will getcha a cuppa bad coffee from a vending machine...but it's pretty cool to get the aknowledgement from the industry.
A word about 3-point Jams and such...
A stoppage induced by an extreme chambering angle isn't a true 3-Point Jam. That normally only results in a failure to go to battery with the shooter able to push the slide to battery. A 3-Point Jam is a different animal that's caused by the bullet nose striking the barrel ramp and pushing the barrel forward...and up. When the barrel tries to time into the slide too early, the front lug corners hit the rear lug corners in the slide...and it all creates a wedging action that is a true jam in which the shooter can't simply push the slide into battery, and has to retract the slide and start over before the stoppage can be cleared. How to tell? If you get a failure to go to battery, use a suitable wooden stick to rap on the muzzle...straignt back. If the round straightens up and the slide snaps to battery...it's a 3-Point Jam.
What many people don't understand is that the barrel ramp isn't a continuation of the feed ramp, and it's not a bullet guide. It's a clearance, and the bullet should contact on the side, right on the top corner of the ramp.
This serves not only to prevent having the barrel move forward and up too early, but also to place downward force on the barrel and keep it in bed...which maintains a less acute angle into the chamber, and an easier breakover to horizontal.
Think of sliding a refrigerator up a set of stairs...and how the side of the fridge rides over the corners of the steps.
Lastly...Jackie has indicated that CMI will make the full-tapered "Hardball" magazines if the demand is there...but the hybrid is a superior design.