I had some issues with my Pre B CZ85 magazine brake. It was bent/warped and I couldn't get it straight enough to not interfere with the magazine. I even filed a little bit of the metal off the front side of the frame posts where the grip screws thread in. That is what the brake "stops" against when it moves to the rear. I thought maybe they were adding to the brake interference a little. That didn't help either.
Then I noticed that both the P07 and the P09 had exposed hammer springs/guides in the back of the frame. Pull the magazine, look inside the well and there is the spring/guide. So, I took the magazine brake out of my CZ85 and never looked back. I figure the CZ85 is no more likely to be submerged in the mud/sand, etc. than my P07 or P09. Makes it so much easier to put a drop or two of oil on the hammer spring, too, when I do a 6 month field strip/clean/lube on it (no longer carried, just another gun I like but find harder to shoot with the iron sights and glasses).
Which also might be a reason that I can use some of the Mecgar 19 round magazines???