NFA NOSLER BOTTLENECK 6.8 SPC?? What other calibers?

So I was looking at the NFA NOSLER BOTTLENECK 6.8 SPC 16" Pistol upper. I noticed the caliber selection in the drop down, along with some exotics.<br><br>Can you imagine a 6.5 Grendel sbr? 10mm, 30 carbine, 9x39, or the Grendel sbr? <br><br>Thanks for the info, it's been real!