Not sure if anyone has ever had this issue but my forend is a bit loose, and can shift left and right a bit and is not tight.
What can i do to fix this movement?
Is the forend tube nut tight?
Remove the barrel and the bolt. Look in the forend opposite the action bars. I have used a pair of needle nose pliers to tighten it but there is a specific tool for the job if you really want to buy it.
And when you tighten it, hold the forearm tightly in place, centered between the slide bars. If not, as you tighten the nut it will shift towards one side too much and rub against the barrel when your pumping. Hope I explained it well.
If you want the tool, you can find them on eBay pretty cheap.