Strange vertex Stretching

Here’s the file.

If you render it, it works fine, everything moves is sync, but when run in the game engine, two out of three times around, one of the smaller cylinders has this awkward vertex-stretching thing that looks like cheap m-bluring. I can’t tell if it’s bad parenting/grouping, or if something beyond my knowledge is going on.

When I play it frame by frame with my arrow keys, It looks fine, so I don’t think it’s the parenting. Please check it though.

If you’re wondering about the file, it’s going to be a chaingun, like the one from UT3.

Hmm, it looks to me like you havent done a ctrl a in object mode. So one of the barrels isnt oriented correctly with everything else. It goes to its global location, which isnt the same as it looks in the 3d view in either edit or object mode.

I would suggest checking all your axis and making sure they match. then add the bones, then the ipo.

did you use vertex parenting for anything. I know that it can distort things, there is a way around that though. Also try what ititrx said if it is not that