I'm not sure what specific fitments the Stag-10 is compatible with or if it takes any AR-10 compatible handguard so my apologies if this suggestion is incorrect but I have a Paper City Firearms handguard on an 11.5" AR-15 upper that I bought from Arms East. I rather like the thing, its M-LOK and has integral QD mounts front and rear on both sides, the scallop texture feature on the bottom is rather unique too. I noted that they make the same style in AR-10 fitments: ht tps://papercityfirearms.com/online-shopping/paper-city/handguards/g2-ar10-16-5-hand-guard
I would be a bit cautious. There are like 3 different AR-10 handguard types and the G2. When it says G2 in the name, I want to believe it’s for a DPMS G2.
The Stag 10 takes DPMS high handguards.