Mine is that way aslo. The magazine tube is sort of concave, and the plastic part of the hush stalker rubs on the outside edge of the magazine cap. I've had the gun for 5 years, and the only place the paint is missing is that little ring where the sling rubs on the magazince cap. I've since switched to a small more compact metal swivel, and it fits just fine, and doesn't rub anywhere. The hush stalker swivels were too wide/long.
