As far as I know, the MX4 has the MX8 action but the action sides are ground flat to reduce weight. I had an MX4C with factory screw-in chokes and a drop out trigger and the nicest wood you ever saw. I bought it in England years ago and sold it, it was a bit light to shoot all day. I have never seen a MX4 in Canada or the US, seems they were made for the European market, hence the nice wood, the Europeans will not tolerate the treated fencepost wood on P guns sold this side of the pond
Mike