While I'm waiting on the bacon to fry I have a quick question. I have a DPMS 5.56 upper. What would I need to do to convert to 6.8? Is a simple rebarrel? Or is there additional steps?

barrel, bolt, and magazine so I have been told

Forgot about the bolt. I "assume" the carrier would work for both

yes, same bolt carrier but the bolt face is a bit larger than .378, 223 size.

Is pretty common to use a mid length gas system for 6.8 barrels from 14.7" to 18". Tends to soften the recoil a bit.

If you do that, you'll need a gas block (if you do not use a barrel with a front sight base) and a new gas tube as well.

In addition, most 6.8 barrels are threaded 5/8x24 so a new FH or brake is required as well. N.B.: Several vendors use 1/2x36 threads for 6.8 bbls and there is at least one other thread in use.

6.8 SPC II is a very useful chambering.

Thanks guys.