Only Bertram.

The other European .416 Rigby manufacturer is Horneber in Germany, and I'm not aware of any Oz importer for them [unless NitroX gets his brass supply venture off the ground].

The US currently only has A-Square,and they have some quality problems apparently.

No word yet if Marc Jamison, of Jamison International, plans to produce this calibre. He bought the BELL production plant, when they ditched sporting brass production. He has got .505 Gibbs in production now, but it's 'wait and see' for others.