Stuck bolt
My dad has a M-100, we took it to a gunsmith to have it broke down and cleaned before deer season, after deer season I was going to clean it I pulled the bolt back but not far enough to catch the magazine when I tried to pull it back again it would only come back about a 1/4"took it back to the guy who cleaned it before season, we tried putting a wooden dowel down the barrel and hammering it open no luck he said the only way to get it apart was to cut the stock off. We decided to send it back to Win. they repaired it but never said what was wrong with it, they replaced alot of parts in the bolt. The only thing we could guess that happened was that a pin came loose in the bolt and locked up the action, this was 20 yrs ago. I know this isnt much help but this is what we had to do to get it fixed. Good Luck deathray