Another lovely photo, Mick. Well done, once again. They must have looked pretty fancy out on parades in that gear.
The rifles certainly do look like Lancaster rifles, probably reduced bore type, that were widely issued to Victorian Forces after purchase in 186, though I do believe that some Ordnance type were used earlier than that. In any case, the chape and lockets of the bayonet scabbards visible have the distinctive look of the Lancaster bayonet scabbard.
There is another quite nice photo of soldiers in the same uniform in the "Early Muzzle Loaders in the Victorian Volunteer Forces" article in the Articles section at this site:
http://mhhv.org.au/?P=745 (I still have trouble attaching web addresses in the flash way some of you other blokes do.)
Lancer 17, what are the markings on your Lancaster bayonet that identify it as a Victorian issue bayonet? Is it numbered to the gun?
Donny B.