How to plug a Canuck hunter

[u/Tristan1477]

I just bought this Canuck hunter 20 gauge used and it didn’t come plugged. I cannot figure out how to get the mag tube open to insert a plug. Tried prying the circle cap you see out figured as is was like other spring retainers but didn’t budge, any help is greatly appreciated.

[u/xthemoonx]

Looks like this is what you want but its currently out of stock.