Atlas rail mount

You mean JUST the mount-portion of the Atlas bipod?

If so, I have honestly NEVER seen one for sale before. You might contact Kasey here on the Hide or otherwise Accu-Shot directly by phone or e-mail and see if they can sell you one. If you have a BT10-NC and are just looking for a mount, go ahead and opt for any number of different QD options. Makes moving the bipod on/off different rifles a WHOLE lot easier/simpler as no tools are required.

If you mean a complete BT10 Atlas...check with Triad, MHSA, or any number of other Hide vendors who'll likely have inventory.
 
I have the bt-10nc. Had an Arms mount that broke and I just don't feel like spending $70-90 on another right now.

The ARMS mounts are renowned for doing just that...BREAKING!! ;)

The ADM mount is a MUCH better product in every respect, but particularly the adjustments and the strength of the lever and mount as a whole. I know its a big pill to swallow, but its worth the price of upgrade. If you don't go that route, good luck with trying to obtain a 2-screw clamp mount from B&T.