Had the TF 20 round base pad on my MPX 30 round mag- Using my loader put in 49 rounds then it - the loader- came off-
The 50th round went in by placing it on the top round- and with a stout bang on the base pad the round went in.
The mag will not lock in on a closed chamber- with 49 it will-
Functioned just like a factory mag- no feed issues what so ever.
I recommend this base pad- great TF product.