hey yall i just picked up the home defense 18 in barrel for my mossey 500.... when i got home i noticed that it wont fit on the standard magazine tube.... is it ment for the 8 shot tube???
I, too, have a Mossberg 500 which I fitted with an 18-inch barrel. Mine fit. If the takedown screw is too far away from the magazine, then you may be right that is is for the 8-shot
The distance from the end of the barrel's flange that slides into the receiver to the inside edge of the flange holding the takedown screw is 15-13/16 inches on my 18-inch barrel.
Take a look at this barrel chart. I aam newbie to this but have been figgering out what barrels I can add to what, and I don't think there is a Mossberg 18" barrel. There is an 18 1/2" and a 20". BTW there are also Maverick 88 barrles that will fit Mossbergs. I am guessing you got a 20" barrel for a 535 Mossberg security.