on my rings,i put the new 2 ring setup on and noticed the bottom ring when lined up with the little pin would stick in the groove when i pushed it in hard by hand,so hard in fact i had to use a knifeblade to help pry it back out,i tried both rings on the bottom,same results,so i got some 600 grit paper,layed it on a flat surface and lightly lapped the flat surfaces of the rings,when i did this for just a min i looked and noticed a R stamped on one side both rings next to the end gap,but also noticed these rings have a slight beval on one side to the inside and completly flat on the other,,the r is on the beval side also,,,anyway now the rings fit into the groove and no sticking,,stamped r go up both rings?