my HW-55M does not have beeman markings. as I mentioned in my earlier post mine has the 14 oz. sleeve and I was not able to remove the sleeve with all the power I could muster with my hands and a tack rag even with the front sight and grub screw removed so I stopped short of heat or other means to remove the sleeve,as IMO it gives good balance to the gun and I like the fact that it is as it was it was meant to be(original) as shipped from the HW factory.