Just got done extending the mag on my 223. Extended it to be able to running 2.5" cartridges. Have it running as reliably a factory plastic 223 mag I have to compare maybe a little bit better actually.
A brief overview is I trimmed the upper metal tab and rebent the lower tabs to be shorter by the same amount. I did this using a vice and a bit of stock ground to the space I wanted. I then trimmed the bottom cap and moved all relevant bits backward by trimming, filing or adding a pin.
I then installed the spring upside down so the long end was in the follower. I had to remove the support rib at the back of the magazine to do this.
While I make no guarantee this will work for you it did for me and I will continue to test it.
A brief overview is I trimmed the upper metal tab and rebent the lower tabs to be shorter by the same amount. I did this using a vice and a bit of stock ground to the space I wanted. I then trimmed the bottom cap and moved all relevant bits backward by trimming, filing or adding a pin.
I then installed the spring upside down so the long end was in the follower. I had to remove the support rib at the back of the magazine to do this.
While I make no guarantee this will work for you it did for me and I will continue to test it.
