rifle detonation again

[Kurt]

I rung a chamber in a .45-120 Pedersoli using a full compressed load of black powder.
I had a hang fire, click----bang. The only thing I can contribute it to maybe moisture in the case from cleaning the cases. I think the primer pushed the bullet out of the case and when the charge went off it did the damage.
There was a guy at the range that had a brand new I think IBA .45-120 and I asked him how did you load it and he said 3031 cant remember how many grains he used but I asked him are you using a filler to hold the powder down and he answered just a thin wad, I told him don't shoot it and I told him what will happen.
I walked back to my rifle on the 300 yard line and he shot on the 100. pretty soon he came over asked me if I had a cleaning rod with me. I asked him stuck case and he said yes I have one I cant get out.
I didn't tell him I told you so.