you lost your magazine....but then you said it doesnt seat properly...did you buy a new one or what? if the mag isnt seating properly thats your problem..could be the magazine..i do alot of shooting with ar-15s,ak-47s etc etc...some guns just wont function with some magazines. some i can see wearing on the paint/finish/metal that shows whats hitting and causing malfunctions and ill file that down..also..id definently break the gun down and clean it. may be a pia to do...but from my expiriences the sprays and such work..but to a certain extent. they move the dirt and grim around but alot will get trapped in there some place or another. taking it to a smith isnt a bad idea...if the smith is knowledgeable he will beable to figure it out pretty easily...