Help me about my Webley 455.

[H3nkk4]

I have a Webley 455 Mk"IV",and i like to know when its make. And i have just found some empty brasses to reload, and i have found a reloading table from a reloading book,but the table was made for Webley Mk"VI". I do know that mine is som years older and i like to know if i can fire smokeless powder in it,for example Vihtavuori N320. I dont want to shoot it if im not 100% sure.