My new 336 BL is the same, only put 30 rounds through it and just noticed it tonight, not sure if it had any movement out of the box, if it did I didn’t notice it anyway. Tried to tighten the screw that goes through the end of the mag tube into the dovetail, but it was already tight. It’s going back to the shop to get new XS sights put on when they arrive so I thought I’d ask them then. But by the sounds of things it might be assembled correctly and not a problem??