I wish I had seen this thread before I bought a set of roll pin punches from Brownells. Mine mushroomed, too, on the very first use. I also bought their special non-roll pin punch for removing the bolt catch roll pin. This thing broke didn't mushroom, it just plain broke! And it's not like I'm a clumsy oaf with my tools.
My old non-roll pin punches (unknown manufacturer) have gotten much more use and look brand new. However, I feel they do damage the roll pins a bit, so I'm still searching for a good set of roll pin punches. I guess I'll try the Lyman's at Midway.
Anyway, thank God that Brownell's has a satisfaction guarantee.
And that'll teach me not to consult the gurus at AR15.com BEFORE I BUY ANYTHING!!!
Edited to add: I dearly love Brownell's, too, and won't hesitate to buy all kinds of other stuff there in the future.