Here is a magazine holder for the gauntlet2, it will attach to the front (or anywhere there is a m-lock slot) of the stock with m-lock bolts/nuts. The fit is primarily friction and it seems to work just fine, but I added a small void to accept a small button magnet (3mm x 6mm neo magnet) .

The magnet would require you to epoxy a small section of metal to the mag (or a matching magnet with the correct pole orientation), there is a void on the mags that this would allow this, but would require you to do some mods to your mags, this may or may not be desirable.