I am around power level 820 in Destiny 2. I was thinking of doing some exotic quests. These guns would drop a bit above my power level and as I progressed they would become obsolete. In the future if I want to can I match the guns power level to mine so I can use it again?
Yes you can by infusing guns into your exotics you will sacrifice the higher power weapon to bring the exotic weapon up to match its power level.
To do this hit details on any weapon and hover over the first tile to see a list of weapons available to use for infusion.
You can only infuse wepons of the same catagory.