Thanks Geetarman and RPGM1A,
I do not think the magazine is the problem... I have measured it and it is 1.014/1.015 wide which is within spec. and it fits into the receiver when the receiver is out of the stock. But, before I start sanding away I will visit (and register) at
http://m14tfl.com/upload/index.php.
Thanks again for the quick and helpful responses.