Does anyone here successfully load for the Snider? BAW? I have a nice Mk.III 3-band volunteer rifle by Barnett, London, with a VG+ bore, and would like to get it shooting. I have looked at the 'driving-band' bullet designs becoming popular in the US, and the body-filler base-plug idea for the minie-bullet, but can't make the dimensions work in my rifle. Its bore is ~.577, but groove diameter is ~.610. Chamber dimensions will only allow a bullet diameter up to ~.598 to chamber freely in my rifle. Anyone here mastered this?

I frequently lurk (and infrequently post) at the Pommie Mil Rifle forums, but haven't yet declared my ignorance there! I asked this question on the Aussie Hunting Net but no-one knew what I was talking about! (not a stainless synthetic!)

Reluctant to open up the chamber, but starting to considering it! Any suggestions?

A friend of mine loads for his.
The bullet used is the Lyman 575213-OS which is a hollow based minie simply held in a brass case. Upon firing the bullet moves out of the case and the skirt expands to .610 just like a muzzle-loaded minie.
Load is 70gn FFG. Cases by Bertram.

Marrakai
I have just bought a .577 mould for my Tower. Its a minni design. Don't know if it will help but you can have a look at it. The moulds made by Bugg from SA.

The original Snider projectile is basically the 577 Minie ball with the base filled with a clay plug to give better obturation into the rifling . You could try filling the base with something like commercial wall filler - that stuff you fill the cracks in your house wall lining . I dont know what you call it , but you will know what I mean .

Even the last of the Snider projectiles had this clay plug in place. I would get an appropriate sized mould before I altered the rifle chamber- change the chamber and devalue the gun for ever .

Go to the British Militaria Forum and all can be answered there. You can make it work.

The darn bullet is supposed to expand to bore diameter, it won't ever be what you do with cartridge guns nowadays, and you should never alter a collector piece. If you can't deal with it, sell it.

if i understand your problem you have a chamber smaller in dia. then groove dia.
This is realy a problem an undersize lead bullet will not shoot accurate because gas stream with the bullet in the barrel and influence the bullet. A minie bullet will not be so good as it seems, in facts it will in most times not 100% seal.
you can change the chamber for a bigger bullet but I will never change an old gun and believe you think also.
fill the minie hollow base with grease and set a thin over powderwad. this help sometimes.
have you use plastik sabot for a pistol bullets, maybe the plastik hollow base of this sabot work better.
do you know the "kompressionsgeschoss" for the austrian lorenz rifle ?. this design is allmost forgooten but may help.