pardner pump mag extention

[fatcat4620]

I have a pardner pump that had a 28 in. barrel I cut down to about 19 1/8 in. I have heard that the plus 2 mag tubes for 870s are to long for the pardner protectors but only by an half inch or so. With my barrel being half inch longer than a protector will the plus two extention fit my weapon flush?

 

[fatcat4620]

If anyone has a +2 mag tube extention on a remington 870 could you measure the overall length on the extention. That should answer my question. Thanks for looking.