From the picture i notice that you have a short exhaust? Notice that in a rocket mass heater a lot of the heat is taken out through a long exhaust tube, the barel is not all the heat transfer surface. For trying it, it is ok.
It is no measure of health to be well adjusted to a profoundly sick society. -Krishnamurti Tiny ad:
BWB second printing, pre-order dealio (poor man's poll)