I got a bunch of 303 ammo.The head stamp is SMI over 957 I cant find this. does anyone know what this is ?

Societa Metallurgica Italiana, Campo Tizzoro, Italy. Euro designation would be 7.7x56R.

Wow now thats a mouth full...Thank you

Just a word of warning on .303 surplus. The POF headstamped ball is starting to go bad. It is going sour and hang fires on the Pakistani ball even when it has been properly stored. I think it is a breakdown of the cordite due to the age.

Cordite does not go bad, the primers do.
Cordite can be wet for a long time and never go bad. The Vaseline in the mix really helps the strands of propellant stand up to just about any climate.
I reload Cordite that I have collected over the years from dud ammo and some of it is from before WWI. It all works well in my reloads.
The primers on the other hand did not like being wet or the production of the primer pellet was rushed and the quality was not the best.
A few years ago I was contacted by Navy Arms and was asked if my club wanted to purchase a large amount of .303 'Battlefield Pick-up" ammo that was collected by the Indian Army from one of their Wars with Cashmere.
We bought 50,000 rounds of the ammo and found most was OK to shoot but there were hundreds of rounds that were not going to go bang.
I still have about 10,000 rounds of this Hodge-podge collection of ammo from just about any maker who ever supplied nations with .303 ammo.
You need to read the head stamps and figure out what propellant you have and which bullet was used. Knowing this will help with rounds on target after you adjust the sights.