The new magazine design was likely discontinued due to a serious design flaw. If you have one of the new magazines, do this:
1. take your floor plate, spring and follower out of your new magazine body
2. disassemble your pistol
3. insert the disassembled magazine body into the pistol grip and lock it into place
4. from the bottom of the grip, insert your follower while the pistol is upside down
You will notice the magazine follower hits the (new) steel magazine catch and stops there. If you take a ball point pin or some other instrument you can push the follower through, note it will take considerable force to move the follower past the magazine catch.
Pushing the follower back out will cause a small indentation on the follower. To avoid damaging the follower, depress the magazine catch and let it fall out without touching the magazine catch.
The follower is of a different design than the original. Here is a couple of pics showing them. The new one is on the left and the old one (original) is on the right.
Here's a shot showing where the follower hangs up:
You'll notice there is no relief cut on the new follower to allow it to pass the magazine catch without snagging on it. As I noted, pushing the magazine follower back down while in the magazine body will cause this damage:
I only pushed it down once and this ridge appeared. The top of the follower is rounded, but given time and enough firings the magazine catch will begin to deform the follower. This will increase friction and ultimately will result in the follower becoming stuck in the magazine body while inserted into the pistol.
There have already been numerous reports of this happening. About the time I started reading about it on the 'net, Ruger mysteriously ran out of parts for the magazines.
Buuzzzt. They realized there was a problem after sending thousands of these magazines out and now they're once again redesigning the magazine and/or looking for a new vendor.
I HIGHLY recommend you do not carry one of these new magazines for personal defense. Use the original magazine until Ruger comes up with the new design. Once they do, call and bitch and make them send you a redesigned magazine. That's what I intend to do.