Only from what I've read on some of the gun rags, they seem to be first-rate mags, with the latest-version followers, etc.
The only thing I would be concerned with (and please, this is only my PERSONAL opinion--with NO empirical data to back it up) is any wear you'd have on the aluminum mag well from a steel magazine going in and out.
But causing any wear on any part of an AR-15 isn't much of a concern when you're puttin' rounds down with an M-14.
Right? :wink:
Spike