McLernon,
Thank you for your interest. I do not know how to describe the gas action so I will remove the fore-end stock and photograph the forend section of the barrel and post the picture here in a few days. My best guess is that it is the same as the 7400, but just a guess. It does have twin action bars for sure. Regarding jamming, as long as I load three or less in the magazine, no jams period. With four in the magazine, there will be an occassional failure to feed the top round completely into battery, but never a problem with 3 or less. Preparation of the magazines is critically important to avoid interference with movement of the bolt. If the lips of the magazine show any gouging or scratching as a result of being rubbed by the bolt, they must be filed down and polished smooth. I do not know anything about the 750's gas action.
mh