As you may know i have picked up a very cheap RWS Excalibur. Resealed,all good.Made a new probe,all good. pellet on pellet Tested at 20yds, (length of garden),till get down the farm, But the gun does not have a air gauge fitted .now the stock has the hole for a gauge an i have a gauge ,but the thread i have on the gauge is 1/8 bsp (i think that is correct) so i need a step down so it fits the gun, does anyone know the thread size (there is a grub screw in at the moment)its the hole between the bolts holding the stock secure. forgot to say the previous owner claims he broke the gauge ,dont know if he meant the gauge or broke it off the gun, i would suspect the first, Many thanks .