Fire Dog,
The 'can' that you describe on my barrel is a 7" vented extension and does nothing to suppress sound.
It does however allow the rifle to comply with ATF standards and permit the use of a buttstock with a barrel that exceeds 16 inches.
The New Zealand website that you refer to is one that hosts the listing of statistics regarding the late, great, Don Bower, contender shooter.
I'm right here in the saddle of the Blue Ridge mountains of Virginia, on East coast of what used to be the USA.
I like shaping wood to compliment the gothiclines of the little break-actions.
357/44 Bain & Davis![Image](https://i.postimg.cc/x130BZZy/357-B-and-D-with-bipod-sm.jpg)