Well I'd guess it almost doubles the cleaning time. I can clean a batch of 250 (38/357) cases in about 3 hours with a fresh batch of media (1+ lbs). Also, I toss in a couple of used dryer sheets cut up into smaller 1/4 sheet size--they realy due hold a lot of debris. I then dump in my Cabelas separator to separate the brass from media, and dump the media back into the tumbler. Running the second batch through on this media seems to take between 4-5 hours to get the same level of cleaning as the first batch. I typically dump the batch out after this. I've never weight the amount of media I dump into the machine. My cases don't come out as clean as wet tumbling with stainless steel pins, but they are a whole lot cleaner than when they get dumped into the tumbler--and I don't have to dry them when I take them out--but you do need to check cases for errant pieces of corn cob. I ran a huge batch of brass through my tumbler about 2 weeks ago now: 950 (38 Special), 1650 (357 Magnum), 300 (9mm), and 100 (45 acp). I didn't go through quite a whole 8lb bag of corn cob media. The tumbler ran about 40 hours that week.