I also own the Shooting in Realistic Environments DVD, and the first thing you need to remember is that Rob Pincus says to NOT change to "bullets back" if you've spent a lot of time practicing reloads with "bullets forward" in your pouch - therefore, it is a relatively minor point in the grand scheme of things compared to maintaining and preserving your muscle memory for performing a slide-lock reload at speed in a critical situation.
Here's Rob Pincus' "bullets-back" reload explained, step-by-step:
- With bullets pointing backward in the mag pouch, the support hand comes back and down to acquire the magazine, palm facing forward; the index finger still indexes along the front edge of the magazine as with a "palm-backward, bullets-forward" reload.
- Upon withdrawing the magazine from the pouch with "bullets-back," the wrist remains locked as your elbow drops(i.e. your bent support arm pivots upward from the shoulder), bringing the top of the magazine to the pistol butt in a direct arc-ing motion; the pistol is brought back from full extension, into a "Compressed High Ready" position close to the sternum, for the reload.
- Insert magazine fully, chamber a round by fully retracting and releasing the slide, fire if necessary from either compressed high ready, extended strong-hand-only, or fully-extended two-handed Isosceles.
In the video, Rob Pincus says he prefers this "bullets-back" method because the support-side elbow does not flag itself out to the side as much as with the "bullets-front" method(i.e. less exposure from behind cover, less chance of hitting your elbow/funny-bone nerve in tight quarters), and because the movement is slightly more efficient(with "bullets-forward," you have to rotate/twist your wrist along the long axis of your forearm to get the magazine oriented properly to feed it into the magazine well).