I got the version of this gun with the 18.5" barrel and the 5 round magazine tube. I want to upgrade the capacity to the 7 round tube but because of the barrel design you would have to replace the barrel to do it.

apparently there was/is a version of the 500 with a 20" barrel that allowed the longer mag tube to be used and came to flush with it, but i can't find this barrel anywhere. any ideas where i can find it?

thanks in advance.

on most of the 500's, because of how the barrel screws on, you can't add an extension to the gun.

with say an 870 or a Winchester, the magazine isn't really capped, the barrel screws into essentially a threaded pipe.

on teh mossy, it's pretty much sealed off and won't allow a shell to pass through the hole that the barrel bolts into.

I personally don't like the extensions...some of them have a tendency to back out under recoil.

as for ordering a barrel, check with Brownell's or Cheaperthandirt.com (that's where I got my shortie barrel)

honestly though, I'd just keep the 18.5 barrel on it, it's a little easier to negotiate in a house and you better hope you don't need the extra two or three shots you'll get from the extension.