FX Streamline...can I do this?

I got my streamline back from fx usa a few months ago but travel and dove season have kept me from shooting it. Today i pumped it up and tried to put the magazine in and it wouldn't go in. It seems as if the barrel (brass colored breech part) is too far back. Can i loosen the set screws on top and move the barrel forward a bit and retighten them? Or should it go back to fx usa one more time.
 
No problems. Put it back together and the scope was still zeroed. Happy. The original reason to send it in was the action was jammed and i felt i wasn't getting the accuracy i should for an fx. I was also getting more velocity variation than my unregulated marauder. Things seem better but i only got two groups in tonight. But one of them was awesome. .44 inches 5 shots at 50.
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So we will see.