I had the same experience as the OP when I took my Bx25 out the first time... I haven't really used it since then, but the normal Ruger mags I had at the time were feeding fine.
I was using Golden bullets and Federal bulk pack predominately, but I even threw some Velocitors in the mix to see if I could get the Bx25 to behave... no dice, it was choking on everything, I don't think I got through 5 rounds without a failure to feed. I was pretty disappointed because other folks seem to be having good luck with these mags.
I hadn't heard about the Burrs though, I may have to tear my mag down and look for manufacturing defects when I get the time.