George, you have come up against one of the weakest areas in the whole hobby. I've tried all kinds of different cans and adaptors some have advantages over others. I would recommend keep trying various combinations until you find something that works for you. I've even seen variations in one manufactures cans from one run to the next (including the primus isobutane). I'm sure others can give their two bits. You will find that there is often a fair amount of leakage, which is why we need to stop fueling long before the alky burner comes rolling our way.