The McCormick RPM gives a longer tube than the PowerMag or PowerMag+, it's much like the difference between the 47 Series and ETM Series in the Wilson line-up, and has a follower with the more rounded tip and a slightly longer back leg, that should show less tipping than the standard Devel/Shooting Star follower, though it is still a Devel follower family member.
CMC RPM https://cmproducts.com/railed-power-...-magazine.html
They also have the wider/flared bumper pad that is common on most extended tube 8 rounders.