Finally building my CMMG MK-8 and need the PDF or instructions for the DPMS upper modification.
The MK-8 was the AR10 lower that takes G3 magazines.
Anybody have the PDF file? I contacted CMMG and they no longer have it.
The MK-8 is a .308 lower that takes G3 magazines.

I have what you are looking for but I don’t have any way to post it here. Email me or PM your email and I will pass it along. If anyone else wants it or can host/post it here just let me know.

Thanks Sent you an email your PM box here was full.

Talk about a blast from the past!  Best use of those cheap surplus G3 mags IMHO. IIRC they had no LRBHO right?

Correct, because G3 mags don't have the ability for that.

I remember the Mk8 and was holding out for the completed rifle rather than just the lower but it never appeared.

Just saw this thread when doing some searching. Will post for future folks who are interested in this platform.

I built one of these once upon a time and made an SBR out of it (10.5"). It's a surprisingly reliable gun given its reputation, but it can be finicky about magazines. Some aluminum mags don't fit - not sure why, I assume tolerance issues - and my single steel mag consistently will not feed the first round correctly (manually), even from a mag with only one round in it. But once you sort out your magazine issues, they run fine, or at least as well as you can build them. I assume the magazine compatibility issues are ultimately why CMMG decided not to move forward with this as a product line (not to mention SR-25 mags are just much better on the whole). But as a play for a companion rifle to a PTR-91, sure, it works nicely.

One other thing I would caution about is that your choice of upper is tricky. A lot of the new uppers just don't have thick enough walls for the mod. The high rise-style uppers are awesome for this, but then you're stuck with the high-rise upper. :) I wound up sourcing an old DPMS high upper, and it worked out well. Unfortunately, this makes the entire rifle a bit of a heavy SOB.