What is known about this stamp from a 577-450 MH

Has anybody any idea as to this stamp??/

Ought to be a Mk 1 Powder, probably made for a contract to Egypt

Not sure if this is the same caliber, looks longer then yours
Is yours a 500/450 or a 577 / 450 ? looks like a 500/450,
be low is the 500/450 or No. Carbine.

No Ammo one this is the 577-450 MH case the 500-450 is different.

Yes I know a 500/450 is not the same as a 577/450 M.H., it was hard to tell by your picture, accept for the length .
That is the only head-stamp I have with a NO.1 on it .
I can check my person collection if you wish.
Was hoping to help.

Also known with a K (12:00) I (6:00) headstamp but with a lower paper patch.That would be the military version & with the Kynoch spelled out the “civilian” version.

Thank you Pete for trying to help,it is astounding how little is known about this stamp,I understand
there was a mark one in 1871 and if this is one of the early cases but than you say there is military
and civilian stamps?? It was one of the reasons I requested a sales list from the late JOHN BELTON
and there was quite a bit of unusual stuff but not that stamp and he specialized in Sniders and
Martinis,will just have to let it go for now.
Thanks again Sherryl

Not an iron-clad rule, but usually British ammunition made by one of the commercial makers, Eley, Kynoch, Kings Norton & etc, used only their initial(s)** for British military contracts and the full name for their commercial product, which might have been part of a (foreign) contract to Egypt or sold to the public.
The reason why I thought this may have been for the contract was because of the high (long) patch, the K I mentioned above has a patch of typical height.
The first of the drawn-case MK I powder were not headstamped.

**You can see this illustrated by looking through your .303"

Thanks Pete
What ever it is I learned something again,that there can be a difference between
military and civilian stamps thanks