A friend sent me a Jr Gent 1 RB a while back,after turning I started to assemble the pen kit.I didn't use the refill that came with it but I replaced it with a Schmidt 888 refill but it won't fit,everything looks the same but the Schmidt won't go down the full way.I was going to buy a few from him but I'm not sure now.Not sure where he bought them from.Has anyone any ideas whats wrong.