I have a Mossberg 500 with a side saddle on it. It's about 10 yrs. old and has 500 or so rounds through it. Took it out today to do some blasting. Put 4 in the tube and went to rack it. It stuck. I mean it stuck hard. Bolt is jammed about 1/2 way down into the receiver and the foregrip can't be budged. First round is still in the mag tube. The chamber is visible empty. Anybody have any idea what caused it and/or a possible solution? I am glad this happened on the range facing a mean looking piece of paper!