I have tried all of the aforementioned tips and spent a good deal of time cleaning the bearings and knife edge of the beam. I am not sure how to check that it is perfectly in the middle; it seems to fall into only one position.
I had to re-zero. 4gr check weight ((2)gr): 4.3gr
Pulled the check weights out and tested them on my digital: 4.0gr
Looking back at the 10-10, the zero needed to be adjusted again.
Before re-zeroing, I tried lightly bumping the beam to get the pointer to go through another full range of motion. This worked once, causing the pointer to return to true zero. I added the same check weights: 4.1gr. Pulling them off, no longer at zero. I then did the bump trick 5 or 6 more times, and it still would not return to zero.
Im not sure if I should exchange it with RCBS or simply get a refund through Amazon... I was told that the 10-10 was about as good as it gets before going to an analytical (which I simply cannot afford). Perhaps I'll try another brand - 3 bad RCBS/Ohaus scales (one I do believe was damaged) is simply too many. It seems to be the older scales (15-20 years ago) that get such high praise.
Thank you all for your help.