I also have a Chiappa M4 .22 and have been firing it for about 6 years and finally wore out the barrel . I experienced a problem with the bolt spring as well . The small guide rod had broken on it . I found a cheap screw driver of the same diameter cut it down and fashioned a new one . The one end of the rod has a pin to hold it to the block and the other is just over sized to keep it in place . For the fat end I put a roll pin over the cut down screw diver drilled a hole through the roll pin and the rod using a drill press and then pinned the two parts together . This worked so well I made a spare but have never needed to use it . Pictured below . Maybe if you send me some pic's we can come up with a similar fix . The .22 I have has been a great little rifle and I will probably replace it soon