Valve grinding compound in the rings \\\it is a sandy grease will mark your tube but there will be no slip slide \\\having scoped rifles in. 577 \ 510 wells express \ 500 ne \ 460 wby \458 \416 wby & rem & Taylor \and its a lotttt harder to keep a scope on the 378,378-338,378-30 wby non of the brits or germs have this hv energy to deal with lots of recoil and highest velocity recoil in the world so \\\ tally rings the grease and Leopold \\\me and the US gov found out the hard way the old continent scopes they are good cost 3 times the PRICE do the same job \\\ all market hype and flash if you need to whiz away the cash and show off have a ball \\\ they all shoot good some cost 2/3 's less took me $32,000 us in scopes \\\ and 6 months w snipers shooting em to get it \\\ so think about it