Actually, we did, just improved (grin). The FN-MAG machine gun was created by Dieudonne Saive by flipping a BAR lock mechanism upside down, so that a belt feed on the top was possible.
The Army rejected the MAG because it was "Not Invented Here," but finally, thanks to the tankers(!), saw the light, and the M240B/M240G is an Americanised FN-MAG.
But you can think of it as a belt fed BAR (grin)
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