Gap of 0.003" is usual from my experience,any less and the fouling drags,0.005" shouldn't cause any problem,I hear of those that open the gap up to reduce binding and deepen the chambers to take more powder but there's no substitute for the right charge.
Also found CCI magnum 11 and the right nipple size for them to be important for 777,not so with BP and Pyro P is not worth trying imo.
Shoot it lots and don't be disappointed if it's not 6 in the black first time out.
Maybe try 6 caps to make sure they all go before loading.