what happend?
 

Went out last weekend to shoot my new 870 12 ga. Well I bought some remington high velocity 5 shot 3 in mags for it. I pulled the trigger and the primer went off and the powder just burned up and smoked. i jacked the shell out andsaw it was melted towards the top. Took the barrel off and noticed the wad was still 3/4 of the way towards the muzzle. So i pushed it out. there was no shot in it. I took the bolt out and inspected everything everything was fine. So i shot a #6 2 3/4 shell out of it fine. i think it was just a faulty round and do not want to shoot anymore of those shells. any one ever see this or no what happend?

Sounds like a bad load to me. Someone did a poor job of quality control. Without the pressure supplied by the shot column, the powder would just burn up.

no, it was light. the shot must have came out when the primer went off.