From Nordic:
Turkish Shotgun Statement
There are a lot of companies importing shotguns made by different Turkish Gun makers. We have found there to be a lot of inconsistency in some of the components from lot to lot as they are manufactured. Many of these guns are advertised to be a clone of a more popular gun, such as a Benelli M2 or Benelli M4. We have never seen one that is an actual clone of one of these more popular guns. We do not know of one that will fit your shotgun specifically, but there are some things you can do to check if maybe one of the ones we currently make will work for you. If you have access to other shotguns from some of the more common gun models you can try the magazine caps from some of these and see if they fit your shotgun. Sometimes ones from a Benelli Nova, Remington 870, or Stoeger 2000 or 3000 will work on these other guns. If you find one for another gun that fits your shotgun, you could order that extension.