I'm looking for reloading information on the .577/.450 Martini Henry.

Has anyone here reloaded for it?

What powders and any special treatment required?

Projectiles? Primers?

I can get brass from Bertram and dies from Simplex.

400 grain lead bullet, 38.0 grains of IMR-4198

NitroX,
You might want to visit BritishMilitaria.
Most 577-450's have a large .460" or larger bullet requirement, which is often met with paper patching .458" soft bullets. The oversized necks may require frequent neck annealing. With the price of brass, you will want to extend its life as much as possible.
I've been forming excellent Brazilian CBC 24 gauge shotshell brass, but CBC Berdan primers are meant for shotshell pressures, and RWS and others are not available to me here in the US. I suspect that Australia may be better supplied with Berdan primers.
Cheers from Grayest California,
Ross

Hi Nitro
In 3rd edition of ADI handloaders guide

577/450 Martini Henry 24" barrel
400gn lead projectile 37gns AR2207 for 1300fps.

Regards
Deafdog

A while back I got Berdan primers from "the old western scrounger". He had quite a choice available.
Good luck1

I'll second the recommendation for the British Militaria Forum at http://pub7.ezboard.com/bbritishmilitariaforums/ and the British Guns forum at http://www.britishguns.net/ as well.

Kynoch is now making loaded ammo and brass for the .577/.450 again, too. I just received 20 cases from them and they appear to be very good, and with boxer primer pockets. We'll see after they've had a few loads run through them. BP is best, of course...