Hfc Hg-196 (Box Cannon) Short Magazine

[UncivilMango]

I was wondering if the shorter magazines for the hg-196 (box cannon) are on sale anywhere? The only evidence I have seen for them even existing is some guy was selling his gun with one on some other forum, but that was more than 5 years ago and no longer for sale.

Do any of you guys have any ideas?

Thanks