The Ar7 is the worst gun I have ever owned.It felt good to get rid of it.Jammed all the time and poor accuracy.Feeble construction and rough machining.My Chinese SKS, feels like a Kimber, compared to that POS AR7.
Sounds like your SKS has mag issues.
I'm not an AR-7 fan either. My friend has an original Armalite, and the trigger is the worst that I've ever felt.