buddy of mine with the bca 18" got ahold of a box of the factory ammo when he was up north over the weekend enjoying having his Hybrid 46 out of NFA jail finally.
with the mid length gas system on that barrel, even with his suppressor on - hornady factory sub ammo did not cycle for him.
anyone tried any other subs in that config? he said they were stupid quiet, but without the cycle ... kinda takes the fun away without at least a side charger.