Hatsan pump mag tube, need 1 inch more

[G-Force24]

Hey guys,
I have a hatsan escort pump that fits 7+1, I need about one inch more so it will fit 8+1. I can't seem to find any tube extensions.

Is there anything I can adjust to gain that inch or more so the spring isn't fully compressed, but won't hurt lreliability? Or do I have to look at a custom job.

Cheers

 

[Ganderite]

The thread is quite common. I bought an extension on ebay. It is a TacStar (adds 2 shots) marked Benelli Nova, Super Nova.