USA Brand magazines have one of the WORST reputations for functioning out there. You will run into some people who will have had satisfactory results with them, however the overall consesus is to run away from them like they are contaminated.
FWIW- MECGAR makes a lot of different companies OEM mags, and also sells them under their house name. If its a MECGAR I wouldn't hesitate getting it.
Good Luck,
Rob