You might be tamping it improperly. That's what I was doing for ages and it was super frustrating. You need to "hot tamp" as opposed to "cold tamp." Basically, when you to damp, mighty press your tamper on your ash, but puff away while doing so. This allows your burning ash to reach fresh tobacco, as opposed to putting the darn thing out.
Credit to someone here for pointing that to me. Can't remember who it was, but it totally changed my piping experience