Re: Rcbs 10-10
"I realize that I can put weights under the sliver pan if it comes to that, but......"
That's the pan hanger and the little chamber under the screwed-on cover on the hanger bottom is for doing exactly that.
Take the screw out, then put the screw, the cover and all the little weights under the cover in your substitute Lee pan and set it on the pan hanger with the scale on a reasonably level surface. Put both poises at zero and turn the leveling screw so the body appears near level. THEN add or remove small weights in the pan until you obtain a near perfect zero (it's not necessary to be precisely zeroed at that point). Put all the weights under the hanger cover and replace the screw and you will be done. You will then be able to use the leveling screw to precisely zero the beam with nothing in the pan and you will be ready to go.
No matter what weights go under the pan holder's cover, it won't affect the accuracy of your weights at all, a beam scale only needs is to be balanced at zero. Then you can add powder to the pan and reset the poises until it balances again. The extended range weight won't be 500 gr., that's just the scale's extended range. The actual weight should be stamped on the brass top - mine is 260.9 gr. You can use that brass 'range extender' weight as a precision test weight, I'll bet that if your agate V block bearnings and the beam knives are clean, and the knife edges are un-burred, your scale will swing twice and stop dead on.