Guess I can let this cat out of the bag now...
I was lucky enough to time an email to ATRS updating my contact information with the partial completion of my build. Since I also had parts that could be used to complete the build and was conveniently making a trip to Calgary a couple weeks later I was able to stop by and the guys put the last couple finishing touches on my MV! I resisted posting this to prevent breaking the internet/ATRS' phone lines...
I went with a light contour stainless barrel, and for what I want the rifle for (3 Gun Competitions, general NR blaster, and maybe the odd coyote) I think it will be perfect. Note the light contour barrel is actual .625 not .750 as originally suggested on the order page. I had ordered mine with an A2 stock, which was the part missing, but had a PRS on hand that we used to complete the build. The PRS is a little heavy for the light weight barrel, but it actually balances out the rifle quite nicely. I like the way it handles now but I may try it with a lighter stock at some point too to see how I like that.
My general impression of the rifle: WOW! I really don't think anyone is going to be disappointed based on what I have seen on mine. Fit and finish on the receivers is excellent, as you would expect. Timney trigger, JP buffer system, Lilja barrel, nothing was skimped on here. Side charging system seems really well designed, with a steel dust cover and track that could be replaced in the unlikely event you managed to damage it. Nylon guide is a neat touch as well. BCG appears to be a DPMS modified for the side charging handle. This is the only part that feels 'basic' on the rifle. I would have gladly paid a little extra to have a higher end chrome/NiB put in I think, not that I have had or anticipate any issues at all with the supplied BCG, just seems a little basic compared to the other components used. My rifle has functioned flawlessly with every load and magazine I have tried for over 100 rounds.
On to the Fortis hand guard... As several have suggested, clearance to the gas block is very tight. My guess would be around .010" at the bottom of the gas block, maybe a little less. I don't intend to use my rifle as a bench rest / bi-pod shooting rifle, but it will be shot off barricades with a 6'2" 225lb man leaning into it at targets as far as 400-500 yards, so this was a little bit of a concern. There is a little extra meat on the bottom of the gas block and at my request/suggestion ATRS has agreed (great service here!) to remove ~.035" from the bottom of a gas block for me, bringing the total clearance to hopefully ~.045". This should be close to the same clearance around the top of the gas block where the gas tube is housed. I expect this modification to be complete and ready for some more serious accuracy testing next weekend. I believe the better long term solution to this (for the light contour anyways...) however is a re-design of the light contour barrel to use a .750 gas block. No reason for a .625" barrel to have a .875" gas block seat. For the heavy barrels sure, but it's not only overkill on the light, as we have seen is actually causes clearance issues with the slim light rails that guys ordering the light weight barrel are likely to go with. This along with the BCG are probably the only two parts of my rifle I would change, pretty minor overall. *Edit: Okay maybe I would add something in to retain the JP silent buffer assembly in the receiver extension tube as well... but again this is a pretty minor nit-pick.
Accuracy so far, even with the gas block clearance has been respectable (though I have been shooting off bags trying to not put a lot of flex/stress into the Fortis). With no load development I have been shooting just over MOA with Sierra 69gr Match Kings and Varget. These were loads I had worked up for another rifle. Even more impressively the rifle has been shooting 1.5 MOA or so with bulk 55 grain bullets loaded into mixed headstamp brass over surplus powder. I am pretty confident with the gas block clearance increased and some minimal load workup this will be a sub MOA rifle with match bullets, which will exceed my requirements for a lightweight barreled build. Realistically I will probably shoot some groups off a bench one or two more times, and unless there are major issues that will be about it for shooting groups with this rifle. The rifle is already more accurate that my Daniel Defense (which was pretty darn good for a chrome lined barrel...), so I see no need to obsess over it. I would imagine the heavy barreled rifles will do even better.
Thanks again ATRS, after only a couple weeks this has definitely become my go-to rifle. So much so it even has me considering a MH at some point...
Guys be patient... it will be worth the wait!