Not a good pic - but you get the idea.


 

Modifying the mags has four steps:

1. Cut the slot in the other side. You can use an existing factory mag as a template if you wish. I used to have nominal dimensions but I lost them.

2. Remove the "bump" on the other side of the magazine body under the AR-15 mag catch hole. Failure to do this will result in the magazine being extremely tight in the gun. This is the most difficult step to perform with metal mags, if you want to flatten them as I did. I used a pan-head bolt and a nut so I could screw the nut on to get in in the mag and then screw it off to tighten it in the mag body, then hammered the bump out. Alternatively, you can file it off, or use a plastic magazine and file it off.

3. Lower the BHO shelf of the back of the magazine's follower by .1". Failure to do this could result in a broken BHO lever and unreliable operation. Parts for these guns are rare.

4. Lower the "tunnel" that the BHO shelf rides through by .1". Failure to do this step could result in a broken BHO lever and urnreliable operation.

I have convered Lancer 30 round, Thermold 20 round, and USGI 30 round magazines and have had 100% success and reliability.


EDIT: Read the whole damn thread, Chris.