Stay away from Promag! They are very low quality. The best aftermarket magazines are made by Mec-Gar but the best are still factory magazines.
BTW: There is a difference between magazines and clips. Here is an example. The one on the left is a clip for a M1 Garand and the one on the right is a magazine for a M14.
USAF Retired, CATM, SC CWP, NH NR CWP, NRA Benefactor
To preserve liberty, it is essential that the whole body of people always possess arms, and be taught alike, especially when young, how to use them... -- Richard Henry Lee, 1787