It could require a different combination of buffer & spring, or possibly enlarging the gas port IF NECESSARY (the last course of action). Unless you try it first, you won't know exactly what would be needed for it to cycle properly and lock open on the last round.
Additionally, you may look into a suppressor for quieting it down for when you do shoot subs, as there isn't much of a point to shoot subs without a suppressor.
My 2 cents?
Purchase a barrel with a pistol length gas port location. It will be less hassle with subs. Oh and buy a can.
fwiw- I have an 8" SBR w/ an Aero 300 barrel with a pistol gas location. It cycles and locks back on all combinations.
Super/Unsuppressed
Super/Suppressed
Sub/Unsuppressed
Sub/Suppressed
eta- I'm using an LWRC UCIW stock kit on that SBR.