1) Download the magazine by one or two rounds and try again. If it no longer jams you are probably using low powered range ammo (Winchester White Box or similar full metal jacket stuff.) Load the magazines and let them set loaded between range sessions and the magazine springs will loosen up a bit. (The next round in the magazine is pushing up against the inside of the slide, causing friction.)
2) Your recoil spring is a bit too tight. Lock the slide back and leave it that way between range sessions.
3) Fully load a magazine, but make the first round a full powered defensive hollow point load. (You know, the buck-a-round Hornady Critical Defense type stuff.) If your problem goes away and you can shoot a full mag, then see 1 or 2 above.
Chances are there's nothing wrong with your Star that a few hundred rounds won't cure.
Also, it wouldn't hurt to field strip the gun, clean it thoroughly, and lube it at the appropriate points, including the rails. The Star is a 1911 style, and 1911s like to run very wet.
Here's a good site for information: http://www.star-firearms.com/firearms/guns/s/
And from that same site, here's a PDF of the manual: http://www.star-firearms.com/firearms/manuals/downloads/a,b,m,p,s_manual.pdf
Only shot 5 rounds at a time on testing.
Thank you very much!