Hi Schwims,
Though completing all bounties and having the armor on when turning them in is the best way to level gear. Try wearing the armor you want to level up while engaging in Strikes and Raids set to the hardest level you can. Vanguard ROC Strikes are a good place to start.
Hope this helps.
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Raids do not provide experience in large quantities. Strikes, patrol missions, and public events are better options.