need advise!

I am brand new to this forum, and also new to auto pistols. I purchased an S40 last summer, and have put ca. 600 rnds through it. today the flage on the sring guide rod broke. Is this a normal occurance for only 600 rounds? This doesn't seem to reliable to me. I have only shot winchester target loads in the gun. It also does not seem to shoot to accurate. From a bench I can only get about 8 - 10 inch groups at 15 - 20 yds. I realize it isn't like my 7 1/2" barreled revolver, but I expected better than this. Any suggestions?