I sent you a PM, in answer to your PM to me. The comments mentioned by other here are valid; I am now convinced that someone in the past has, indeed, altered the chambers in your rifle, so you need to determine exactly the dimensions of the chambers, see that they both are the same, and you need to have a custom, specially made, die set made up for the rifle, to allow you to handload for it. DO NOT FIRE ANY MORE STANDARD .318 CARTRIDGES IN THE RIFLE, for it obviously is no longer chambered for those cartridges. I really hate it, when someone alters a rifle in this way, but it has been done numerous times in the past, and will, no doubt, be done numerous times in the future---a sad state of affairs, but a fact.