From what I'd read, the AR10 ran very well and it was only when they scaled it down to 5.56 for the M16 did it really start having all those teething issues. Even now, the only negative things I read about the AR10s are that the parts are somewhat proprietary and less common than the Ar15, though you don't exactly see M1A parts all over either.
Now, I do agree, and this is not based on any particular evidence, that the M1A will probably be more reliable under harsh conditions than the AR10. But, I don't think the AR10 is any less reliable than the AR15, and there are many specimens of those showing great reliability.
Last edited by Lindenwood; 12-13-2011 at 04:09 AM.