Got to try the Butler Creek 25 round mag today. First I tried Federal Champion, that is a medium quality HV ammo with a 40 gr lead bullet. First magazine after firing the first round it jammed the second. Pulled the bolt back and the 3rd round chambered ok. Fired it and the forth round jammed. Cleared it and chambered the 5th round. After that I was able run the magazine. Reloaded it and again it jammed after the first shot but then it worked perfectly for the rest of the magazine.
Then I switched to the cheap Wally World bulk Federal with the copper washed hollow points. Ran 2 mags of them with no problems at all.
So at this point I'm happy with the functioning of the steel lips Butler Creek. However I probably will usually use the standard 10 mag because I don't care for the length of the big mag. The big mag is fun for bouncing tin cans around in the back yard.