I use powdered graphite, it doesn’t get any easier. I bought a tube (1#) of it years ago & have used it ever since.

I simply stick the end (mouth) of the case (neck area only/stop where the case shoulder begins) in the tub of graphite & give it a quick twist. Then I pull the case out, give it a tap on the side of the tub & give the case neck a wipe with a dry cloth to take the graphite off the outside of the case. Simple, it only takes a couple seconds to lube the inside of a case/case neck.