Misfire

[JamesW]

Out shooting rabbits the other evening and had a misfire of sorts; the shell fired as normal but the shot seems to have left the wad nearing the end of the barrel just before the choke area leaving lead fouling in the last 3", mate standing besides me said there was heaps of smoke.  This is a 16g full choke barrel and was the first shot of the evening, clean barrel with a very light oil smear (will make sure to run a dry patch through before shooting in the future!)  Winchester factory #6shot ammo.
 
Was this due to the oil (couple of drips of light oil on a cloth run down the barrel before storing) or is it just something that shotguns do?
 
Any suggestions greatly appreciated as I would rather this never happen again.
 
Cheers,
James

[dukkillr]

I had a batch of bad Rem shells several years ago where the powder either got wet or was defective.  I had what are describing happen 2 or 3 times during a hunt.  I threw that box away and never had it happen again.  It can be VERY DANGEROUS.  If you hear anything amiss, stop and check the barrel.  For me the wad did not clear the end of the muzzle.