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Lever arms, Hical, Marstar, Tradex are all places that might have what your looking for. Placing a WTB add on the ee might be a good thing to do as well.
Honestly it seems like parts aren’t worth it, especially large parts... I saw an add on the EE a while back with a bolt, bolt carrier, gas tube and gas port for 250 and even that one went quick. Just buy a whole sks lol