mossberg 500 combo; is there a quality tube extension?

[mettle]

I've got a mossberg
Bought as hunter, came with spare barrels
Is there a magazine tube extension or am I out of luck?
Is there a kit to add another 3 or 4 rounds to the thing?
It is this model

Mossberg & Sons | 54243

 

[OneEye]

The only option you have is to get the barrel and tube for the home defence model. Big bucks for three extra shots. I will post more on how to do this later.

http://www.brownells.com/magazines/...arts/high-capacity-shotgun-kit-prod25124.aspx

A link above shows a kit with oem mossberg components like what I was talking about above

 

[downlinx]

I know the 870 magazine extension fits the 500, but then you will need to cut off the 500 cap link to put on a 590 cap. Other than totally cutting Ito you barrel, you could get 590 extension and 590 barrel and nut.

 

[mettle]

I know the 870 magazine extension fits the 500, but then you will need to cut off the 500 cap link to put on a 590 cap. Other than totally cutting Ito you barrel, you could get 590 extension and 590 barrel and nut.

Any way you could clarify this some more?