Winchester model 42 problem.|Winchester Shotguns|Forum|Winchester Collector

Hello all. Im new to this forum and really like reading about all the interesting topics. I am not new to Winchester shotguns as I own many model 12s, and have shot them mostly in trap and skeet shooting. A few years ago I started getting into the model 42 Winchesters. I had an opportunity to purchase a model 42 (serial number 1347XX) that was kinda rough, but the price was right. It had almost no blueing left, but the bore was perfect. I decided to send it off to Simons in Kansas for a new vent rib and reblue. After getting the shotgun home I was really pleased with how it turned out. About a year or so later I took the shotgun out to bust some clays so-to-speak and found that the mag. would only hold two shotshells, on inserting a third shell it would promptly empty all the rounds out of the mag tube. So I didnt get to awfully excited about it and shot it with only two shells in the mag. each time. Well its the holiday season and I have some time on my hands and thought I would look into the problem. There is no mag. plug installed and thought for sure one of you folks might have run into this prblem before. Thank you in advance for any help you might offer. Happy Holidays one and all.