The upgraded backstrap worked great. The upgraded MR didn't hold up for me though. After about ~350 rounds it began dropping mags every time I fire, just like the original. I really like the LW frame but need it to be more reliable. I'm waiting to hear back from JR on upgrading to a production frame.
We will soon release the (final version) MR. This version is absolutely the best ever however it may not correct the accidental mag drop issue. FYI: There are multiple issues contributing to this problem that are not present in all prototype frames. If you are not satisfied with the performance of your prototype please return it. Believe me, no hard feelings what so ever! The latest prototypes manufactured last week are FABULOUS! Absolutely no MR issues. All mags drop free, no chance of accidental release.