Just wanted to give a shout out and a big THANK YOU to Brian at Expressimo Audio!
I had an older Expressimo Heavyweight counterweight for a Rega tonearm. I am rebuilding a Rega Planar 3 from parts and found a great deal on a Rega RB301 tonearm here on Audiogon.
I went to use the Expressimo weight and it wouldn't fit? Seems Rega changed the diameter of the end stub on the RB301/303 series of arms.
I contacted Brian and sure enough the diameter of the RB250/300/600 series of arms was ~.501 and the new arms are ~.508.
He told me to send it in and he would take care of it. He charged a very nominal fee and turned it around the same day! Now that's service.
Got it back today and fits perfectly.