Thanks for the explanation , now it's pretty clear. I'll have to look into the DVD I'll have to measure the catch, but don't think it sticks out quite 1/8". Since I already lightly filed the mag I have, it no longer "slips" out. I have to double check, but I don't think I can simply push the mag and click it into place ...I think I have to check the mag catch pushes in all the way because things are tight. .