Howdy/.303 Brit question/.577 Snider question

[falcon5nz]

I'm new to the forum and thought I'd introduce myself.
My names Nick, I'm 18 and I collect cartridges. I use the IAA Forum a bit but a home grown resource will be good.
2 questions.
I have CAC .303 round headstamped N/CAC/Z/.303(9/12/3/6) Can any one enlighten me as to age/commonality? I always thought they were CAC/MK/Year as those are the only ones I have seen.
I bought a live .577 Snider round for $15. No hstp, but it is apparntly 1880-1885 Vintage made by CAC with the Witney Patent. Can someone tell me if that sounds plausable and give me some info on that.

[byrd]

Hi Nick, this web site may help you,
http://www.dave-cushman.net/shot/303headstamps.html

Byrd