current R10 owners - Barrel Nut Question

They’ve had at least 2 different handguard designs for that blaster, so you would have to pull the handguard off and take a look at it.

The R-10 is basically a militarized DPMS G II, so whatever is available for the G II should be compatible with the R-10. There are several different handguard options in the aftermarket that DPMS coordinated with before they released/revealed the G II at SHOT.