I would recommend the MPN: SP-4002 if you are looking for something with 0 MOA and MPN: SP-4602 if you want the 20 MOA version. Spuhr also offers other MOA values for their mounts if you are interested, please email us at techsales@opticsplanet.com and we can find a different option depending on what you are looking for.
I contacted Spuhr directly and they replied as follows, which some of you may find helpful:
"Thank you for your interest in our products. For the Barrett I would recommend the SP-4016, SP-4616, or the SP-4022. The SP-4016 and the SP-4022 are both 0 MOA but differ in the length of the cantilever (where the SP-4022 provides additional eye-relief) and in that the SP-4022 does not have a bubble level built into the rear face of the mount body. The SP-4616 is a 6 MIL/20.6 MOA version of the SP-4016. You could use the same mounts for the Tikka (A Tac 3x A1 which I also wanted a Spuhr mount for), but if you don’t want to use a cantilever design you could use the SP-4602 (6 MIL/20.6 MOA) or the SP-4902 (9 MIL/31 MOA). All mounts listed are 38 mm from the top of the Picatinny to the centerline of the optics. Yours sincerely, Sören Franson"
I ENDED UP ORDERING THE FOLLOWING:
Spuhr 34mm Cantilever Riflescope Mount, Black, Height- 38mm/1.5in, SP-4616
SPR-MT-34CNTLM-SP-4616
WHICH WORKS PERFECTLY.