Seals used within lead bores of implantable medical devices for creating a seal to implantable medical leads inserted into the lead bores include an inner cylinder that engages the lead body. The inner cylinder is surrounded by a gap to either an outer cylinder of the seal or to surrounding structures of the implantable medical device. The inner cylinder has freedom of movement within the gap such that movement of the lead body that is off-axis relative to a centerline of the lead bore causes movement of the inner cylinder that is providing the seal. In this manner, the seal engagement to the lead body is maintained during this off-axis movement of the lead body.