I just took mine off to adjust how it’s sitting on my carbine (It canted right again.) It got me thinking, what if I broke or rounded the hex on one of the 4 little hex screws that lock it onto the barrel nut, what do you replace them with?
Would you be able to get one off DD if you cant find one at the hardware store?
Call John at DD. He can probably hook you up with one.
sounds like a problem bro… who installed it?
How many times have you had issues with the rail canting to one side?
As I am still trying to decide on my next rail purchase and was leaning towards DD, the lack of anti-rotation devices on all of their rails (except for the RIS II) leaves me wondering.
Mine needed a slight adjustment after I installed it the first time. It looked slightly canted but after reinstalling the rail system it was perfect. 
Another thing you can do is use a riser-rail while your setting the screws. That helps me keep it 100% lined up on the top side anyway. Still have to pay close attention, but it makes it easier. Once they are set, they are very solid. For a drop in rail, I think this is about as good as your going to get. If I was planning on dropping this carbine repeatedly, then this would not be the way to go.
If anti-rotation is a concern, step up to the d-ring removal rail systems from ARMS, MI, or Troy (I know people hate ARMS, but their #50 SIR is a good product IMHO). If you want absolute confidence and rigidity–then the DD Lite-rail/M4 RISII/MK18, LaRue or KAC RAS/URX systems are great!
Once you do a couple of Omega’s, they’re really pretty easy to do. Its the first one that take some getting used too. Sort of like Ultimak’s on AKs 
(and I don’t even have to use hair gel or beeswax on the Omega!
I did! hahaha! All kidding aside, rounding the hex screws was just a thought that occurred to me after installation.
As for the rail, it’s on straight now.
The Omega is a pretty solid rail. Canting occurs mostly during installation but is easily resolved by simply locking it straight with a carry handle or riser as suggested below, or even by hand. No biggy.
Daniel Defense has excellent customer service. You can contact them and they will be sure to take care of you. I had issues with my hex screws rusting and they sent me a replacement set on their dime. Good people to deal with.
THanks!
i use a Larue SPR mount to hold the upper and the rail before tightening screws. not so much for side to side cant, as you can see that easy, more for the levelness front to back. The first time i did it by eye it pitched up towards the front sight.