Remington 40-XBR vs. 40-XBBR

[csaatremsoc]

I own a Remington 40-XBR and have had it for a number of years, but have hardly shot it at all. It is a single shot bench rest rifle chambered in 6mm PPC, I think this receiver was made in the early 70's. I went to the Remington website and can see that they currently offer a bench rest 40-XBBR. What is the difference between the current 40-XBBR and my 40-XBR? I called the company and they couldn't tell me.