Tossed that article on dropping your own bismuth shot into a separate thread in the Shotguns forum HERE. Hope it is useful.

Bismuth shotshells are on the shelf at F&OW at ~$82 a box, No.4 shot size only, 70mm case, 34 gram load, 1340 fps.
Falcon brand, so presumably loaded in New Zealand.

Thats's pretty fast, and a full payload for bismuth in a 70mm shell, so probably running modern CIP/SAAMI pressures.
If so, it kinda defeats the purpose, bismuth being most viable in older guns that can't take the beating of modern loads.

No.4 pellets are available too I believe, in 5kg bottles, but need to be ordered in. I have asked for a price...