Congrats on the 6.8 upper. Bison makes top notch equipment. When you finally do get it, I'm sure you'll be more that happy. My Bison upper shoots 1/2 MOA at 100yards. I bought it used so I didn't have to deal with the supply issue...
They seem to have developed a customer service issue of late. I hear about people inquiring with them and being ignored. It's really unfortunate.
I imagine it just current state of affairs. All the high quality builders seem to be booked for months and months. I think they should at least answer peoples emails. Did they quote you a ship date?
I'm waiting on a .458 SOCOM barrel from another vendor, Black Hole Weaponry. Their lead time is 14 weeks. I have 10 weeks to go. Keeping my fingers crossed.
For everything 6.8mm:
http://68forums.comand for everything Bison there at the 68forums:
http://68forums.com/forums/forumdisplay.php?45-Bison-Armorysam